On the Hypothesis of Light Quanta.

Ramsauer. Die lichtelektrische Wirkung untertheilter Lichtquanten. Ann. d. Phys., 61, p. 750, 1921.

From the standpoint of the hypothesis of light quanta, radiation exists in space (outside matter) in the form of isolated wave trains, whose total store of energy is determined by the well-known relation \(h\nu\). Such a conception gives a simple and easy interpretation to certain physical phenomena (for example, Millikan’s experiments on the photoelectric effect), for which any other explanation proves difficult. But

On the other hand, there are many facts that cannot be reconciled with the existence of light quanta. Thus, H. A. Lorentz pointed out that the ability of light waves to interfere at a very large path difference (more than 2,000,000 wavelengths) leads to the conclusion that the path length constituting a single quantum reaches 100 meters, for only waves belonging to one and the same quantum are capable of interference. Ramsauer, in the paper under review, gives yet another experimental proof of the untenability of the hypothesis under consideration.

The polarization of light (e.g., by double refraction) consists in separating quanta with one plane of polarization from quanta polarized in a perpendicular plane. In doing so, one may assume that the quanta are “sorted” without being split, depending on the orientation of their plane of polarization relative to the principal plane of the crystal. However, if polarized light is split by a doubly refracting crystal into two rays, then each of them must be formed by the division of individual quanta into two parts: \(h\nu \cos^2 a\) and \(h\nu \sin^2 a\), since the angle \(a\) between the principal plane of the crystal and the plane of polarization of the incident polarized beam is the same for all quanta. Moreover, the ability of the ordinary and extraordinary rays to interfere with one another also argues for the splitting of individual quanta in double refraction. Thus, if light quanta exist, they must be split under double polarization; and in the photoelectric effect caused by such light, consisting of fractions of quanta, there should be observed a distribution of the velocities of the photoelectrons as though light of a greater wavelength were acting \((h\nu \cos^2\varphi = h\nu')\). In exactly the same way, the number of electrons corresponding to 1 calorie of absorbed energy should be smaller than in the case of ordinary light, for in the present case the radiation consists of portions of smaller individual energy, i.e., the matter is again reduced, as it were, to an increase in wavelength, and the influence of the photoelectric function of the normal effect should appear. Ramsauer studied the photoelectric action of such twice-polarized light (250 μμ; 436 μμ; 546 μμ, and weak white) and could not detect any deviations from the ordinary laws of photoelectric action. Thus, in this experiment as well one may see a fact that undermines the existence of light quanta and transfers the meaning of the quantum hypothesis to the nature of the atomic resonator.

G. S. Landsberg.