The method used by Hylleraas in treating the He atom has been extended to the H2 molecule. The method consists of setting up a wave function as a series in the five variables required, electronic separation being introduced explicitly as one of the variables. The coefficients are then determined so as to produce the lowest energy. The energy found is within 0.03 v.e. of the most probable experimental value, while the form and location of the potential energy curve

The deviation from an integral value found corresponds to a packing fraction of -14 (X 10~4), which is much greater than would be indicated by Aston's curve, provided that cesium is a simple element. Another unexpectedly large packing fraction was recently found by Baxter and Butler19 for titanium, although in this case doubtful indications of another mass line have been reported and the element may not be simple. It may well be that further investigation will prove that cesium is also complex.Acknowledgment for financial assistance is made to an anonymous benefactor of this Laboratory, and to the Carnegie Institution of Washington. SummaryAn analysis of cesium chloride, prepared by the recrystallization of alums of cesium, by comparison with silver confirmed the atomic weight of cesium to be 132.81.

Wave functions of several forms have been applied to the treatment to the ground state of Li. It is found that errors in the representation of the K shell have but little effect on the computed ionization energy, and that a satisfactory orbital for the L electron can be constructed in a very simple form. The best wave function in which the relative positions of the K and L electrons are not taken into account gives an ionization energy in error by 0.05 ev. To take

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The validity of the Franck-Condon principle has been investigated in connection with its application to the calculation of spectral intensities in the continuous radiation due to the transitions between the 1sσ2sσ 3Σg and the 1sσ2pσ 3Σu states of H2. For the latter state, a potential curve was constructed on the basis of the authors' theoretical calculations. For the former state, a curve was computed from spectral data by Dunham's method. Accurate wave functions for both states were determined by mechanical integration with the differential analyzer. Transition probabilities from the first four vibrational levels of the stable state were determined by mechanical integration, both for the case that the electric moment matrix element is constant (as assumed in the Franck-Condon method) and for the case that it is a linear function of the nuclear separation. In addition integrals were determined which permitted the calculation of the probability of excitation of the several vibrational levels by electron impact from the ground state, upon the basis of an extension of the Franck-Condon method. The spectral intensities so obtained are compared with those given by several forms of approximate calculation, and the discrepancies critically discussed. Comparisons are also made with the experimental work of Smith and of Finkelnburg and Weizel. It is concluded that the Franck-Condon principle leads to results definitely incompatible with their observations. Indications are found that other transitions than the one treated in this work are contributing appreciably to the radiation observed by Smith. An analysis of the spectrum observed by Finkelnburg and Weizel leads to a critical discussion of the method used by them in deducing the potential curve of the repulsive state, from which is drawn the conclusion that this curve is without quantitative significance.