MEETINGS AND CONFERENCES

9th MEETING ON SPECTROSCOPY

(Reports at the Second and Third Sections)

The reports at the second section of the 9th Meeting on Spectroscopy*) were devoted to the following questions: 1) excitation and emission of atoms, 2) processes in light sources and problems of spectral analysis, 3) spectral instruments and photoelectric methods of spectrum recording.

On the first question, a total of eight reports were heard, in which elementary processes of excitation and emission of atoms, the width of spectral lines, the distribution of atoms and molecules over energy states in light sources, etc., were discussed.

In the report by S. L. Mandelstam and N. K. Sukhodrev, the question of the applicability of Kirchhoff’s law to the study of gas-discharge plasmas was considered. On the basis of an examination of the balances of the acts of emission, absorption, and stimulated emission of light, the authors established that Kirchhoff’s law is fulfilled if: a) for lines there is a Boltzmann distribution of atoms over excited levels; b) for the continuous spectrum caused by bound–free transitions, there is an electron distribution according to the Saha and Maxwell formulas; c) for the continuous spectrum caused by free–free transitions, there is a Maxwellian distribution of electron velocities. All these conditions are usually realized in the plasma of a spark and an arc at atmospheric pressure, and also in certain cases of discharge in low-pressure gases.

A. A. Dibrova, in the report “Diagram of the Periodic System of Ionization Potentials,” showed that, for determining ionization potentials by interpolation or extrapolation, one should introduce the “mean” ionization potential, equal to the ionization potential divided by the ionization number. These mean potentials satisfy, for isoelectronic series, a linear dependence on the charge number \(Z\).

In the report by S. E. Frish and I. P. Zapesochny, the role of cascade transitions in the excitation of spectral lines was examined. The intensities of mercury lines were determined experimentally as functions of the energy of the exciting electrons. Special attention was paid to the monoenergetic character of the electrons; a photoelectric method of intensity measurement was used. The results of the measurements gave the following: the optical excitation functions of the mercury lines \(\lambda\lambda\) 5461, 4358, 4047, 4078, 4916, 4108 Å have several sharp maxima, located 1–4 V above the excitation potential. The presence of these maxima is explained by the role of cascade transitions. Each experimental curve

*) For a report on the work of the first section of the 9th Meeting on Spectroscopy, see UFN, vol. LV, issue 3.

with several maxima can be decomposed into curves representing the true excitation functions of the individual energy states of mercury. These excitation functions have sharper maxima than had been believed up to now. The presence of cascade transitions is confirmed by direct experiments. In the case of excitation of the visible triplet of mercury, \(\lambda\lambda\) 5461, 4358, 4047 Å, transitions from the \(7^3P_1\) and \(8^3P_1\) levels must play an essential role. The first of these lead to the emission of the infrared triplet, which the conditions of the experiment did not make it possible to observe; the second lead to the emission of the triplet \(\lambda\lambda\) 6907, 7082, 7092 Å. The appearance of these lines was indeed observed at those exciting potentials to which one of the maxima on the optical excitation function of the triplet \(\lambda\lambda\) 5461, 4358, 4047 Å corresponded.

A number of reports were devoted to the application of the method of anomalous dispersion to the determination of oscillator strengths and concentrations of atoms. G. F. Parchevskii and N. P. Penkin applied D. S. Rozhdestvenskii’s “hook” method to the determination of oscillator strengths in the spectra of iron and nickel. Spectrograms were obtained and measured, containing photographs of hooks at the absorption lines of 14 multiplets of iron. The lines belonging to these multiplets arise in transitions from the lower levels of the iron atom \(a^5D\), \(a^5F\), and \(a^3F\). Relative oscillator strengths were measured for 56 lines. In nickel vapor the “hooks” were photographed near the absorption lines of 20 multiplets arising in transitions from the levels \(a^3F\), \(a^3D\), and \(a^1D\). Relative oscillator strengths were measured for 48 lines. The accuracy of the determination for lines belonging to one multiplet is 3–8%, and for lines of different multiplets 10–20%. The data obtained were critically compared with the results of measurements performed by emission and absorption methods. Significant discrepancies were established between oscillator strengths measured by different methods. For lines belonging to different multiplets, the discrepancies reach the order of magnitude. These discrepancies may be explained by errors in determining the concentrations of atoms in the initial levels. When the emission method is used, reabsorption has a large distorting effect. The method of anomalous dispersion is free from this drawback.

N. P. Penkin and M. N. Palladin reported on the application of D. S. Rozhdestvenskii’s “hook” method to the determination of the concentration of excited mercury atoms in a discharge in mercury vapor and in mixtures of mercury vapor with inert gases. The population of the \(6^3P_{012}\) levels of mercury was measured in a discharge in pure mercury vapor and in a mixture of mercury vapor with argon, neon, and xenon. The measurements were made at various pressures of mercury vapor and of the inert gas, and also at various strengths of the discharge current. The optical measurements were accompanied by probe measurements, which made it possible to determine the electron concentration and the temperature of the electron gas. As a result of the measurements, the transition was traced from nonequilibrium populations of the levels to equilibrium populations, determined by the Boltzmann formula, corresponding to the temperature of the electron gas. The mechanism of formation and destruction of mercury atoms in the \(6^3P_{012}\) states in the discharge investigated has been established. It was shown that the inert gas has only a slight influence on the population of the \(6^3P_{012}\) levels of mercury.

A. M. Shukhtin, in his report, described a modification of D. S. Rozhdestvenskii’s method proposed by him, based on compensating the optical length of the column of substance under investigation by the optical length of a layer of the same substance of known particle concentration. The method is applicable to determining changes in the density and composition of a vapor mixture in a gas-discharge gap. In the case of work with a mixture of vapors, the method makes it possible to determine the change in the concentration of particles of each kind selectively. Simultaneously with determining the change in the concentration of unexcited particles, the method makes it possible to clarify the influence of the process being studied on the opti-

chemical properties of the substance (the form of the dispersion curve, transition probabilities, etc.).

G. P. Startsev reported on another new variant of Rozhdestvenskii’s method. He proposed using a three-beam interferometer to measure dispersion near absorption lines. The change in the refractive index near the absorption line causes “splits” of the interference fringes, whose distance from the line determines the magnitude of the dispersion. Two schemes of a three-beam interferometer were used, assembled according to the type of the Rayleigh and Jamin interferometers. In order to test the new method, the ratio of oscillator strengths was measured for the first doublet of sodium, for which this ratio is well known from careful measurements made by the “hook” method. The ratio obtained was \(f_1/f_2 = 2.01 \pm 0.02\), which agrees with the value \(2.00 \pm 0.01\) obtained by the “hook” method. The report also presented a method for taking into account the influence of the doublet components on the measured dispersion. It was shown that the new method of measuring dispersion is approximately an order of magnitude more sensitive than the “hook” method. Comparison of oscillator strengths measured by “splits” at various distances from the absorption lines indicates the absence of systematic errors in the proposed method. At the same time, the correctness of Sellmeier’s formula is confirmed down to distances of \(0.2\) Å from the absorption line.

In the report by V. Lebedeva and V. A. Fabrikant, measurements of intensities in the visible triplet of mercury were reported. It was shown that, when the influence of reabsorption is taken into account, the value obtained for the intensity ratio is \(J_{5461} : J_{4358} : J_{4047} = 71 : 100 : 48\), which agrees well with the ratio \(67 : 100 : 45\) obtained from the sum rule. Results were presented of an approximate quantum-mechanical calculation of the transition probabilities of the lines of the visible triplet and of the intercombination line \(\lambda 12070\) Å. The ratio obtained was \(J_{12070} : J_{5461} : J_{4358} : J_{4047} = 0.09 : 69 : 100 : 46\). The lifetime of the mercury level \(7^3S_1\) was also calculated.

A number of reports were devoted to the width of spectral lines. I. I. Sobelman, in his report “On the Correlation of the Impact and Statistical Theories of the Width of Spectral Lines,” gave a general treatment of the question of line width, containing in two limiting cases both the impact and the statistical theory, and established the limits of their applicability. For the center of the line the intensity distribution is determined by the impact theory, and for the wings of the line by the statistical theory.

I. M. Nagibina gave a report on investigations of the width of spectral lines in an alternating-current arc discharge. An attempt was made to relate the width of spectral lines to the course of the calibration graph. For a number of elements (Mn, Cd, Pb, Mg) the integral relative intensity of the lines was determined, and its dependence on the concentration of the element in the light source was determined. For a certain concentration interval, a linear dependence was established. In this concentration interval the line width in the arc discharge remains constant. At higher concentrations there is a linear dependence between line width and concentration. An attempt was made to explain line broadening in an arc discharge from the point of view of “quenching” collisions with identical atoms.

The report by V. F. Kitaeva was devoted to the study of the shape and width of spectral lines in a direct-current arc discharge. Lines of Na and Tl were studied. The substance was introduced in the form of a charge into the carbon anode of the arc. Measurements were performed using a Fabry–Perot etalon. It was established that, for lines with a small quadratic Stark effect (Na, \(\lambda 5890\), Tl, \(\lambda 5350\)), the width is entirely determined by Lorentz collisions and the Doppler effect. For lines with a larger Stark constant (Na, \(\lambda 4752\)), the width cannot be explained solely by the effect

Doppler and Lorentz broadening. For this line, apparently, interaction with ions and electrons is significant.

Reports by M. A. Alekseeva and V. S. Melchenko were also devoted to processes in a steady-state arc. M. A. Alekseeva used, for determining the absolute concentrations of atoms in the arc, a method proposed by N. A. Prilezhaeva, which is based on comparing the intensities of lines of neutral atoms and ions. The temperature of the arc was determined from a comparison of the intensities of two lines of a neutral atom having different excitation potentials. Measurements were carried out both along points of the arc column and along the radius of the arc. The measurement results for the concentrations of atoms along the column proved to be in good agreement with calculations performed on the basis of diffusion theory. Along the radius of the arc the concentration of atoms changes little. The temperature falls from the axis of the arc to its periphery by \(600—700^\circ\). According to Saha’s formula, the degree of ionization of the atoms was calculated. V. S. Melchenko investigated the influence of self-absorption on the intensity of lines in an arc. Growth curves were constructed for a number of lines, and a deviation was established of the dependence of line intensity on concentration from a linear dependence at high concentrations.

S. M. Kishko and V. S. Milianchuk reported on their work devoted to studying the effect of a jet of gas on radiation from a flame. It was found that, when illuminated, new molecular bands arise in the flame spectrum as a result of violation of the selection rules for transitions between vibrational levels. The question of the violation of selection rules in the field of monochromatic radiation was also considered theoretically.

The reports by T. N. Popova and N. A. Prilezhaeva, V. S. Rassokhin and I. L. Tsikora, and I. V. Veits, L. V. Gurvich and V. V. Korobov, although presented in the 2nd section, were devoted to molecular spectra. In the first of these works, the distribution of molecules over vibrational states in a glow discharge was studied. In the second work, high-frequency discharge in \(\mathrm{CO}_2\) and \(\mathrm{C}_2\mathrm{H}_2\) at atmospheric pressure was studied. The mechanism of formation of the radicals \(\mathrm{C}_2\) and \(\mathrm{CN}\) was discussed. In the third work, the dissociation energy of molecules of metal oxides (\(\mathrm{SrO}\), \(\mathrm{CaO}\), \(\mathrm{MgO}\)) was determined on the basis of measurements of the intensity of resonance lines of metals in the flame spectrum.

A large group of reports (ten) was devoted to the study of processes in light sources used in spectral analysis. S. L. Mandelstam and P. I. Tindo reported on further work investigating the glow of the spark channel. Observations were carried out while varying the circuit parameters, the composition and pressure of the gas, and also the magnitude of the spark gap. The temperature was determined during the development of the channel, and Boltzmann’s formula was investigated for the distribution of atoms over excited levels under different discharge conditions. In the report by V. K. Prokof’ev with a group of co-workers, the properties of a low-voltage pulsed electric discharge were discussed. The process of ejection of a plume of luminous substance, the duration of this ejection, and the emission of individual spectral lines in the region of the plume were studied. Mirror scanning was used to investigate individual stages of plume ejection. It was established that the outflow of luminous substance occurs at high velocities (\(800\ \mathrm{m/sec}\) and more). In the initial stage the ion spectrum is observed predominantly, and in the subsequent stage the spectrum of neutral atoms.

K. S. Vul’fson also studied, by the method of mirror scanning, the time course of the brightness of a pulsed-discharge channel in inert gases. The existence of a limiting brightness was established, indicating the large role of self-absorption of light in the channel plasma. O. P. Bochkov and E. Ya. Shreider reported on the application of pulsed discharge to the spectral analysis of gas mixtures. The investigations were carried out in helium mixtures-

argon and helium-nitrogen. It has been established that, in the spectrum of a pulsed discharge, lines of the difficult-to-excite component arise, whereas the spark lines do not; the latter component is readily excited. This makes it possible to increase the sensitivity of the analysis for the difficult-to-excite component. Hundredths of a percent of helium in nitrogen can be determined. The pulsed discharge can also be used for the analysis of three-component mixtures. A feature of the pulsed discharge that is advantageous for spectral analysis is the very weak evolution and absorption of gases by the electrodes.

The reports by G. P. Skornyakov and G. E. Zolotukhin were devoted to the evaporation of electrode material in the arc. G. P. Skornyakov established the different evaporation intensity of various metals depending on whether the given metal is the cathode or the anode in a direct-current arc. The author believes that negative ions of the metals are formed in the arc. G. E. Zolotukhin investigated the influence of the chemical composition of electrodes on the evaporation rate. Calculations were carried out on the kinetics of thermal processes on the surface of the electrodes. The report by Ya. D. Raikhbaum was also devoted to the kinetics of vapor formation in an electric arc. The author studied the dependence of the time of vapor formation on its mass formation and its thermal constants. The rate of vapor formation increases sharply when the boiling point of the substance is reached. This makes it possible to determine the boiling temperature of metals and their compounds, and also to record the fractional nature of the entry of vapors of various compounds into the discharge.

M. E. Britske reported on investigations of a high-current arc in which the current density reached 70–80 a/cm². The intensity of various atomic and ionic lines and their distribution over parts of the arc were studied. It was found that in a high-current arc there is no enhancement of ion lines at the electrodes. The report by N. S. Sventitskii and K. I. Taganov was devoted to the excitation of spectra by a discharge in a liquid medium. The features of excitation in a liquid make it possible to obtain additional data on the spectra of elements. Discharge in liquids is suitable for studying processes in electrical methods of metal treatment. A. N. Lyulichev and L. S. Palatkin reported on investigations of spark temperature from an apparatus for electro-spark strengthening of metals. The spark temperature was measured from the ratio of the intensities of arc and spark lines of iron. The influence of discharge parameters on the temperature was studied.

Somewhat apart stood the report by M. V. Dolidze, relating to an astrophysical problem. M. V. Dolidze’s work was devoted to spectrophotometry of stars of different spectral classes. It was found that, for stars of the type of P Cygni, the distribution of energy in the continuous spectrum differs from that of the main sequence. The results obtained were used to calculate quantities characterizing the envelope of the star.

A large group of reports (27 in all) concerned questions of new instruments for spectroscopic investigations and spectral analysis. Three of these reports were of a review nature and were delivered at plenary sessions. The rest were presented at two joint sessions of Sections II and III and at two sessions of Section II.

In the large review report by V. K. Prokofiev, two features were noted that distinguish the new instruments from those issued earlier: 1) the wide use of diffraction gratings, plane and concave, with 600 and 1200 lines per mm, and 2) the use of photoelectric receivers for recording spectra. This review presented new instruments of the following groups: vacuum spectral instruments, high-dispersion and high-resolution light-power instruments, interference spectral instruments, spectroscopes, spectrophotometers, instruments for the infrared region of the spectrum, generators for excitation of spectra, instruments for studying spectrograms, and demonstration spectral instruments. In the following reports, the properties of some of ...

of these instruments, and individual questions of their operation and use were considered. These reports can be divided into several groups. Diffraction gratings and instruments using them were considered in three reports. The spectral characteristics of Soviet diffraction gratings were set forth in a detailed report by F. M. Gerasimova, delivered at the plenary session. Here questions were covered concerning the quality of the spectrum produced by samples of plane and concave gratings, the concentration of intensity in individual orders of the spectrum (up to 70% in one order), and the intensity of Rowland ghosts (tenths of a percent). In the report by A. M. Nizhina and F. Z. Pedos, the results of work on making copies (replicas) of diffraction gratings with a sufficiently satisfactory spectrum quality, suitable for spectral instruments with a small focal distance (up to 1000 mm), were presented. R. I. Tveryankina reported on the properties and design of the DFS-2 diffraction spectrograph with a concave diffraction grating (600 and 1200 lines per mm) of radius of curvature 2 m, mounted according to the Paschen–Runge scheme (on the Rowland circle), and of a diffraction spectrograph with plane gratings and a concave mirror of focal length 4 m, assembled according to an autocollimation scheme (DFS-3). Eight reports were devoted to questions of photoelectric recording of spectra. In the detailed survey report by I. S. Abramson and S. L. Mandelstam, “Some Problems of the Photoelectric Methods of Spectral Analysis,” read at the plenary session, the questions of choosing the source of spectrum excitation, the spectral apparatus, the radiation receiver, and the recording scheme for ensuring the greatest accuracy of analysis were critically examined. Radiation receivers (photon counter, photocell, and photomultiplier) were subjected to special consideration from the point of view of sensitivity and measurement accuracy. The report by L. M. Malyavkina and I. S. Abramson set forth experience in using an electrometer with a dynamic capacitor for photoelectric recording of spectra. I. S. Abramson and A. N. Mogilevskii considered certain features of the operation of photoelectric systems with spectrum scanning when recording spectra of combination scattering. Ya. S. Bobovich and D. B. Gurevich reported on the construction of an instrument with a large-surface plane diffraction grating (150 × 150 mm²), with a photomultiplier, amplifier, and mirror recording of the spectrum on photographic paper from a galvanometer; illustrations were given of the use of this instrument for recording spectra of combination scattering.

T. K. Falk described the design and principal properties of three spectral instruments with similar photoelectric recording of the spectrum: an exit collimator (\(f = 300\) mm) for the ISP-51 spectrograph for recording the spectrum in the region 4000–5400 Å (PS-381); an exit collimator (\(f = 800\) mm) for the ISP-51 with two photomultipliers for recording the spectrum in the region 3600–10000 Å (PS-382); a spectrograph with a plane diffraction grating of 600 and 1200 lines per mm (\(f = 1200\) mm), with the possibility of recording the spectrum from a photomultiplier and also of photographing it on a photographic plate (DFS-4). I. V. Podmoshenskii and L. D. Kondrashova reported on the design and working experience of a photoelectric 8-channel unit with a concave grating of 2-meter radius of curvature, with photocells and a readout scheme based on the principle of charge accumulation with subsequent logarithming and obtaining a readout proportional to the logarithm of the relative intensity. In the report by S. A. Kulikova and A. V. Yakovleva, the construction was described of a fluorite vacuum spectrograph with a photon counter as the radiation receiver. For the purpose of obtaining greater spectral purity, doubling of the optical system and obtaining a double monochromator are provided; examples of the operation of such an instrument were given. Finally, Osipova reported on the design and properties of the automatic recording spectrophotometer SF-2m for the visible region of the spectrum.

MEETINGS AND CONFERENCES

The design of several prism spectral instruments was described in four reports. A. I. Ryskin reported on the design and properties of a large three-prism glass spectrograph (ISP-67) with four interchangeable cameras, \(f = 180,\ 500,\ 1500\), and \(3000\) mm; the last camera is autocollimating and gives, in the region of \(4000\) Å, a linear dispersion of about \(0.8\) Å/mm. B. A. Shapochkin, in his report, proposed the design of a two-prism dispersion system operating both at the minimum and outside the minimum of deviation. G. L. Berman reported on the design of a new stylo-meter (ST-7) and on experience in using it for the analysis of a number of nonferrous alloys. In the report by I. I. Gromova and A. V. Yakovleva, I. R. Protas gave a description of a vacuum fluorite spectrograph and of work with it using specially developed Schumann-type plates of increased sensitivity. Three reports concerned spectrum-excitation generators and light sources for spectroscopic work. The report by M. I. Demidov, N. N. Ogurtsova, and I. V. Podmoshenskii was devoted to the design of a low-voltage generator of an arc and spark with electronic control; an original design of a stand with a protective casing was proposed, satisfying the requirement that it produce no radio interference. G. A. Soboleva described her work on investigating the spark and arc regime of the serially produced generator DG-1; the change in the energy released in the discharge was determined calorimetrically, and heating of the electrodes was studied. I. I. Kondilenko and M. P. Lisitsa proposed the design of a powerful hydrogen lamp with a discharge current of \(2\)—\(17\) a.

Instruments for the infrared region were discussed in two reports. L. V. Smirnova reported on the design of two infrared spectrometers, IKS-11 and IKS-6; the latter has a resolving power almost twice as great as that of the IKS-11. Amplification of thermocurrents and recording are carried out with the aid of B. P. Kozyrev’s photoelectro-optical amplifier. A. M. Bonch-Bruevich and Ya. A. Imas proposed an original method for recording rapidly varying processes with the aid of inertial receivers, suitable for the infrared region; the essence of the method consists in matching the frequency characteristics of the receiver and of the electrical recording device.

Two reports concerned work with instruments of high resolving power. F. A. Korolev reported on new methods of using multiplex standards for purposes of high-resolution spectroscopy. He, together with V. Sukhanovskii, succeeded in obtaining dielectric coatings for Fabry–Perot etalon mirrors with low absorption and a high value of the reflection coefficient.

The design of a new original recording microphotometer (MF-4) was discussed in the report by G. Ya. Kossov. The design is based on the well-known and fully proven MF-2 microphotometer. M. Ya. Shapiro reported on the design of a very simple time relay controlling the time of firing and exposure in quantitative spectral analysis. A. K. Rusanov, E. V. Gusyatskaya, and N. V. Ilyasova demonstrated an atlas of spark and arc spectra of elements, prepared by them for the region \(2200\)—\(6900\) Å, obtained with the ISP-22 spectrograph. In the atlas, in addition to the lines (the basis of the atlas), the positions of the analytical lines of 55 elements are given. S. K. Kalinin demonstrated an atlas of spectral lines developed by him for a glass spectrograph in the wavelength region \(3700\)—\(9100\) Å. In the atlas the positions of the lines of 62 elements are marked relative to the lines of the iron spectrum.

The third section—the section on emission spectral analysis—was the most numerous. More than 400 delegates took part in its work. At 9 meetings (including 2 parallel ones), about 80 reports were heard and discussed. In addition, there were two meetings held jointly

with the second section on instruments, processes in the discharge, and spectrum excitation generators. Many reports were subjected to detailed discussion; sharp debates arose. Special mention should be made of the numerous meetings of delegates from industrial organizations with one another and with workers of a number of ministries who took active part in the work of the conference. Along with intensive, truly extracurricular work, industry conferences were held, bringing together workers from enterprises of individual ministries, both during the conference and over the two days after its conclusion. Such intensive extracurricular work resulted from the fact that representatives of the most varied regions of our country had come to the conference; here we met representatives of the Arctic industrial regions and of the Far North, representatives of the Far East and the Baltic republics. Many of these representatives gave reports testifying to the great work being carried out in various corners of our immense Motherland. It may be said without exaggeration that the third section of the past conference demonstrated the great successes achieved in emission spectral analysis in our country over the past two years. This follows not only from the appearance at the conference of representatives of new enterprises and new branches of industry, but also from a number of serious reports testifying to the increased level of work being carried out at industrial enterprises.

In a brief survey it is impossible to state in detail the content of all the reports. Let us consider them by groups.

1. General methodological questions. Three reports were heard here concerning the preparation of standards for spectral analysis. K. A. Sukhenko set forth the results of extensive work carried out by her and a group of her collaborators on the production of standards for aluminum and magnesium alloys, as well as a number of complex multicomponent alloys. Methods were described for obtaining cast and wrought standards and the results of their verification and certification.

The advantages of briquetted standards pressed from powders of various metals were presented in the report by V. V. Polyakova. It was noted that transferring a metal into powder form followed by briquetting leads to an increase in the sensitivity of determination of small impurities; this is explained by the lowered thermal conductivity of such briquettes. In the report by V. V. Styopina, prospects were presented for the development of production of standards for spectral analysis of various steels, ferroalloys, and slags. Four reports were devoted to calibration graphs. I. S. Fishman set forth his further work on studying the reabsorption coefficient \(b\), which determines the slope of the calibration graph in logarithmic coordinates \((\lg J_{\mathrm{pr}}/J_{\mathrm{osn}} = b \lg c + \lg a)\). An attempt was made to determine this coefficient for a number of spectral lines; it was confirmed that spectral lines associated with normal or metastable states of atoms give \(b = 1\). Yu. M. Buravlyov, using some steels as an example, shows that the calibration graphs for these steels are not parallel to one another; therefore the analysis of these steels cannot be carried out using a control standard. A. M. Borbat and N. G. Yakhovich established, for aluminum-based alloys, the non-parallelism of the calibration standards; however, some groups of standards give intersecting graphs; a special check of the composition by control chemical analysis did not eliminate this intersection. S. A. Shipitsin showed analytically that accounting for the background in the spectrum, although it leads to an increase in the slope of the calibration graphs, does not increase the accuracy of concentration determination. In the reports by A. B. Shaevich, Yu. M. Buravlyov, and R. I. Gutkina, results were presented of investigations on the influence of structure and cementation in the analysis of a number of alloyed and highly alloyed steels and cast irons; certain influences were found, pro-

• occurring in the mixing of calibration graphs. I. A. Grikit established the influence of heat treatment on the results of analysis of high-speed steel. Interesting reports were presented by N. K. Rudnevsky with a group of collaborators on the nature of the entry of electrode material into the discharge gap for copper–nickel and aluminum–silicon alloys. With the aid of an original and simple technique it is possible to capture the substance passing through the discharge zone and analyze it. A nonuniformity was established in the entry of material, connected with changes in the thermal conductivity of the electrode materials, as well as a proportionality between the concentrations in the gas cloud and in the solid electrode.

E. S. Kudelya, by means of spark treatment of previously strongly heated or cooled (to the temperature of liquid air) electrodes, identified the influence of diffusion of electrode material on the sparking process. In his opinion, the sparking process consists of two processes: selective oxidation in the surface layer (the work of L. N. Filimonova) and diffusion of elements from the depth of the electrode to the surface layer.

In the report by A. V. Kozlova, P. D. Korzh, and K. Z. Finkina it was shown that the introduction of graphite powder for diluting a powdered sample of stainless chromium–nickel steel and nichromes makes it possible to determine Cr and Mn from a single graph. The powders are obtained on an electric-spark unit. A. N. Vorsin used a flame generator of direct current designed by him for quantitative determination of iodine, bromine, chlorine, and sulfur. V. P. Borzov and N. S. Sventitsky, for a number of alternating-current arc generators (PS-39, DG-1, with electronic control), showed that increasing the reproducibility of analysis with such generators is limited by the errors of the photographic plates. E. L. Grinzayd, K. I. Ionova, and V. N. Nalimov presented in their reports the results of statistical treatment of various sources of error in spectral analysis; especially extensive and interesting statistical material was presented in the report by K. I. Ionova and V. N. Nalimov. The properties of photographic plates of types I, II, and III were set forth in the report by A. A. Frishberg. R. N. Rubinstein and N. G. Karpel demonstrated two nomograms for simplifying calculations in quantitative spectral analysis: one for work in the region of normal blackenings, the other for work with the complete characteristic curve.

2. Analysis of steels and cast irons. A detailed survey report on the spectral analysis of steels and cast irons was given by N. V. Buyanov. This report, compiled on the basis of the experience of many plants, proposes a draft GOST for the analysis, in low-alloy steels, of Mn, Si, Cr, Ni, Al, Mo, and Ti in an alternating-current arc (DG-1), and of Cu in steels, and Si and Mn in refined cast irons with spark excitation (IG-2 generator), using the method of photometric interpolation. A. G. Komarovsky presented the results of his work on the rapid determination of Si, Mn, Cr, Ni, Mo, W, Ti, V, Co, Al, B, and Nb in high-alloy steels and heat-resistant alloys using the method of photometric interpolation. Three reports by O. I. Nikitina, V. V. Sukhovalova, and E. F. Nikitina were devoted to various techniques for determining As in steels.

E. S. Kudelya and A. S. Demyanchuk, using an auxiliary magnesium electrode, sharply reduced the influence of atmospheric carbon in the determination of carbon in alloys and obtained the possibility of determining the carbon content in iron alloys, beginning with 0.02%, using high-frequency and condensed electrical discharge.

3. Gases in metals were the subject of three reports. N. S. Sventitsky presented the results of the work of a large group of researchers

two research institutes on developing a method for determining hydrogen in steels. To excite the spectrum of hydrogen, consisting of the only accessible line, H\(_\alpha\), a pulsed discharge was used. Special measures must be taken to clean the surface of the specimen from organic films and adsorbed moisture. The preparation of standards also presents great difficulties, since many alloys gradually give off hydrogen. A. O. Porshedan uses the excitation of hydrogen to study the adsorption properties of various metals. O. B. Falkova reported on the method she had developed for determining oxygen in steel when excited by a powerful electric discharge in a hydrogen atmosphere. The line 4641.8 Å is used; determination is possible in the concentration range 0.005–0.2%.

1. The analysis of pure metals and of products of their manufacture was the subject of a number of reports: V. F. Pisarev, A. V. Kornilov, and Z. P. Kostrova reported on the determination of Pb, Cu, Sb, Fe, and As in crude tin with the IG-2 generator. D. M. Lifshits reported on extensive work on the spectral analysis of noble and nonferrous metals in ores and products of their processing, carried out jointly with a large group of collaborators: determination of impurities in cathode copper of various grades, in pure cobalt using shavings and cast electrodes, analysis of Au, Pt, and Pd in poor samples without fire-assay enrichment. B. P. Pashevkin reported on the determination of Cd, Pb, Cu, and Fe in high-purity zinc by the method of photometric interpolation of mixed spectra. S. M. Solodovnik reported on the determination of impurities Pb, Bi, Cu, Ag, Al, As, Zn, Co, Ni, Mn, Sn, Fe, and Na in metallic antimony and antimony in antimony ores. P. M. Polyakov and A. K. Rusanov reported on the determination of Al, Mg, Mn, Fe, Si, Cu, Sb, Pb, As, Cd, Zn, and P in metallic vanadium in a direct- and alternating-current arc. Spectral analysis of impurities Mg, Si, Cu, P in titanium during its conversion from metallic titanium to oxide and pressing with copper powder was considered in the reports of Sh. G. Melamed, S. M. Solodovnik, and M. A. Natkina.

2. Survey reports covered work on spectral analysis at certain plants and in biology. A. V. Sokolova set forth the application of spectral analysis in the laboratory of a steel-wire plant for the analysis of thin steel wires down to a diameter of 0.01 mm. On behalf of a large group of collaborators from Gintsvetmet and Altai-Gintsvetmet, the results were reported of work on the spectral analysis of nonferrous metals using the short-wave region of the spectrum and a two-phase alternating-current arc with a moving electrode (N. A. Arakelyan, M. E. Brichke, and others).

L. P. Andreeva described various applications of spectral methods of analysis at the Kuznetsk Metallurgical Combine: analysis of small concentrations of Al, Zr, Ti, Mg, and Zn in steel and cast iron, zinc in electrolytic baths, and others. The very diverse applications of the styloscope and spectrograph at the Severonikel Combine were described by O. Ch. Velichko. N. P. Rubina dwelt on experience in work on spectral analysis at a secondary-aluminum plant: spectral methods of production control, standardization of sample preparation, organization of the labor of laboratory spectroscopists, monitoring of their work, working conditions, statistical analysis of materials, and experience in joint work with the chemical laboratory. A report by A. O. Voynar on the application of emission spectral analysis in biology and medicine, based on the experience of a large group of collaborators, was heard with great interest; the main questions were the qualitative and quantitative determination of trace elements (26 in all) in the human organism and in a number of animals, in some food products, and in soils.

6. Discussion of methods for the analysis of slags and cements was opened by a review paper by N. V. Buyanov, who critically set forth the diverse methods currently used for the analysis of slags; the main task is to develop a method that would not be sensitive to the mineralogical composition of slags. The subsequent papers developed the propositions of N. V. Buyanov’s report. Thus, O. I. Nikitina dwelt on the application of the briquetting method and the method of conversion into solution. D. M. Shvarts and I. S. Nilova, for the analysis of slags of nickel production, successfully used the dilution of oxides and the dissolution of slags. E. N. Lesnikova applied fusion of slags with various fluxes. The papers by T. K. Massilion and Z. A. Koltseva concerned the analysis of cement raw materials, clinker, and the products of cement plants. The analysis of magnesites, magnesite fireclays, and the clayey basic fluxing materials of furnaces was the subject of papers by G. A. Pedan and A. E. Noshchenko. L. V. Drutskaya dwelt on certain special features of the determination of impurities in alumina.

7. Spectral analysis of ores was represented by a large number of papers. The first in this group to be heard was a detailed paper by A. K. Rusanov, “Changes in the temperature conditions of excitation in arc analysis of ores and minerals,” continuing a series of interesting works on the volatility of the constituents of a sample, on changes in temperature in the arc flame, and on the connection with the ionization potentials of elements. In this paper an interesting, original technique was proposed for introducing a solution (by spraying) into the flame of an arc discharge.

In his paper “On the effect of sample composition on the accuracy of spectral analysis of ores,” V. Nedler showed that 1) sample heterogeneity does not play a significant role when it is sufficiently finely ground, and 2) a change in the mineralogical composition of the sample leads to a change in the discharge temperature and to a change in the physicochemical processes at the electrodes. L. A. Spektorov, I. K. Klavdienko, and A. I. Pogulyaeva examined the influence of certain substances present in a sample on the intensity of the lines Mo, In, and Tl. The influence of certain impurities in the determination of rare-earth elements was the subject of a paper by T. N. Zhigalovskaya; she also noted that the limiting determinable concentration of various elements is increased (the sensitivity of determination is lowered) with an increase in the principal quantum number n of the shells of optical electrons. I. I. Smolyak proposed adding calcite to the sample in order to determine the presence of fluorine in it. Kh. I. Zilbershtein substantially increased the sensitivity and accuracy of the analysis of solutions by introducing the precipitate into the surface layer of a carbon electrode pretreated with a 3-percent solution of polystyrene in benzene. A. N. Bronshtein investigated the influence of various additions for increasing the sensitivity of gallium determination in powdered samples. A. M. Shavrin, for the determination of vanadium in ores at concentrations from 0.025 to 0.2%, uses a single standard, having first established that the rectilinear graph holds at an angle of 45° to the coordinate axes. Certain methodological procedures for determining alkali-earth elements from powders and solutions were set forth in a communication by T. F. Borovik-Romanova, V. V. Korolev, Yu. I. Kushchenko, and M. M. Farafonova. The combined use of chemical and spectral analysis in the determination of Fe, Ti, Mg, and Ca in phosphorites was reported by Yu. A. Sherstkov. A very effective methodology for semiquantitative spectral analysis of 40–50 elements in rocks, proposed by M. M. Kler, was developed and widely used in practice by V. V. Khokhlov, V. N. Protopopov, L. I. Denisenko, E. Ya. Smirnova, Z. G. Timonina, and M. M. Kler; information on this was given by M. M. Kler. S. S. Shai-

[[unclear: beginning of surname]]likov reported on work to prepare primary standards for the analysis of mineral raw materials for 50 elements. M. L. Shilling spoke about his work on the determination of tin in rocks. O. N. Nikitina described methods for the spectral determination of Fe, Co, Mn, Ni, Ti, and Cr in quartz and high-silica materials. The determination of Pb in natural waters was the subject of a report by E. V. Guslyatskaya and L. G. Loginova. The determination of V, Ni, Cr, Cu, Si, Al, Fe, Ca, Mg, and B in clays was presented in reports by two groups of researchers: N. V. Astaf'ev, R. S. Rubinovich, S. A. Yakovleva, and E. E. Vainshtein; T. F. Borovik-Romanova and V. V. Korolev. The application of spectral analysis in petroleum geology, with a presentation of certain results, was covered in reports by A. A. Geiro and F. M. Efeniev.

1. Among other applications of spectral analysis, mention should be made of the determination of the thickness of oxide coatings on parts made of aluminum alloys (V. P. Borzov and E. V. Il'ina) by introducing into the pores of the film a specially selected filler. L. S. Evlashchin proposed a method for determining the concentration of tin in a complex galvanic coating for radio tubes. M. P. Grishenko and A. B. Shaevich, as well as Z. P. Golovchenko, presented a method for analyzing various electrolytic baths. M. G. Mal'tsev and K. I. Taganov reported on the results of their investigations into carrying out the spectral analysis of metals and alloys with contact-electrospark sampling. The quantitative spectral analysis of admixtures in lubricating oils was reported by V. P. Borzov and E. V. Il'ina. In the report by K. S. Garger, V. D. Umnova, and T. D. Krivulya, the results of new observations of the spectrum of the Bessemer flame in the visible and near-infrared regions of the spectrum were presented, using receivers sensitive for different regions, and the use of these observations for controlling Bessemer smelting was discussed. Questions of local analysis were covered in two reports: N. G. Isaeva—the presentation of certain applications of a previously developed method; and A. G. Komarovsky—local analysis of weld seams of high-alloy steels and heat-resistant alloys using a specially assembled generator for excitation with powerful pulses of a low-voltage spark, high-frequency discharge, and arc discharge. V. M. Kolosova reported on certain techniques in spectrophotometric investigations of forensic-expert objects and on establishing degrees of reliability in such investigations. M. S. Shpil'ov presented the design of an instrument (an oxigemometer) for the photoelectric, continuous, and bloodless determination of the degree of oxygen saturation of the blood in a living organism.

S. E. Frish,
V. K. Prokof'ev