G. Herzberg. Vibrational and Rotational Spectra of Polyatomic Molecules. Translated from the English by Ya. S. Bobovich and B. I. Stepanov, edited by M. A. El’yashevich, Foreign Literature Publishing House, Moscow, 1949, 647 pp., price 64 rubles.

G. Herzberg’s extensive monograph is devoted to highly topical problems of chemical physics. Rotational and, in particular, vibrational spectra are at present among the most important means of studying the structure and properties of polyatomic molecules. Infrared spectra and spectra of combination scattering of light are finding ever wider application in various fields of technology; at present molecular spectral analysis, based on the study of vibrational-rotational spectra, has entered the practice of a number of branch institutes and factory laboratories.

It must be emphasized that, in contrast to work on emission spectra, which can be carried out to a considerable extent on purely empirical grounds, research in the field of molecular spectral analysis is impossible without a well-developed theory explaining the connection between the vibrational-rotational spectrum and the structure of the molecule. Therefore the appearance of the Russian translation of Herzberg’s book, which contains very rich experimental material on vibrational-rotational spectra, as well as an exposition of a number of theoretical works, should be welcomed.

Herzberg’s book consists of five chapters. The first, short chapter is devoted to the rotation of molecules and to rotational spectra. All the basic types of molecules are analyzed in detail, and the theory of rotational spectra is presented; this chapter is very valuable—we know of no other equally detailed exposition of these questions. The very extensive second chapter contains the classical theory of molecular vibrations. Here one should note the good exposition of questions connected with the symmetry of molecules and vibrations. At a considerably lower level is the exposition of the methods for setting up and solving secular equations for molecular vibrations. Herzberg, a major spectroscopist, is not a specialist in this field, and in his book confines himself to an uncritical compilation of a number of American and Austrian computational works that have substantial shortcomings (see, on this subject, M. V. Vol’kenshtein, M. A. El’yashevich, B. I. Stepanov, Vibrations of Molecules, vols. I and II, Gostekhizdat, 1949). Herzberg reveals ignorance of the work of Soviet authors on the calculation of molecular vibrations; as is known, as a result of the investigations of M. A. El’yashevich, B. I. Stepanov, L. S. Mayants, and others, it proved possible to construct the mechanics of molecular vibrations and to apply it to very complex compounds.

In the third chapter the theory of combination-scattering spectra and of infrared spectra is set forth—that field which, in the Soviet scientific literature, has received the name electron-vibrational spectra of molecules. Herzberg’s exposition of these questions seems to us completely unsatisfactory. The chief reason for this is again the ignoring of Soviet works. As is known, the theory of intensities and polarizations in the vibrational spectra of molecules was first created precisely by Soviet authors (see the cited monograph Vibrations of Molecules, vol. II). In these works Herzberg is not acquainted with it and confines himself to repeating long-known propositions of Placzek’s theory. In this same chapter a detailed analysis is given of the spectra of a number of molecules, beginning with triatomic and ending with twelve-atomic ones. This material is undoubtedly very useful.

The fourth chapter is devoted to the interaction of vibrations and rotations of polyatomic molecules. This chapter contains very valuable data, since insufficient attention is usually paid to these questions. Herzberg examines in detail all possible cases of interaction, touching also upon such phenomena as hindered internal rotation. Certain problems to which Herzberg refers are analyzed in an original way. In the last chapter, entitled “Applications,” a brief characterization is given of thermodynamic calculations on the basis of vibrational-rotational spectra and a description of phenomena connected with intermolecular interaction. The exposition of these questions is carried out at a high scientific level, but contains nothing essentially new. On the whole, Herzberg’s book occupies a significantly inferior position to his two other monographs (atomic spectra and the spectra of diatomic molecules) with respect to the integrity and independence of the exposition. Nevertheless, it will be of undoubted benefit to all researchers,

working in the field of molecular spectroscopy. Especially valuable are the description of all phenomena determined by molecular rotation and the summary of experimental data on vibrational-rotational spectra, accompanied by interpretation of these spectra. In the Russian edition the book has been supplemented by an introductory article by M. A. El'yashevich and by a number of his notes, chiefly bibliographical in character. An extensive list of Soviet works on vibrational spectra is also given—these works had almost entirely fallen outside the bibliography compiled by Herzberg. It must be emphasized once again that it is precisely ignorance of these works, which occupy a leading place in world science, that is the chief cause of the substantial shortcomings of Herzberg’s book.

The translation of the book is good. It has been excellently produced. The price of the book (64 rubles) is disproportionately high and cannot but be an obstacle to its wide dissemination.

M. Vol'kenshtein