fValues for Transitions between the1S1,

Abstract

The Sand P-state helium wave functions recently obtained by the authors have been used to make an accurate calculation of the f values for transitions between the 1'S, 2'S, and 2'S states and the 2'P, 2'P, 3'P, and 33P states in this atom. The accuracy of the results has been estimated by evaluating the dipole length, velocity, and acceleration forms of the matrix element for the transition, and by the inclusion of differing numbers of terms in the expansions of the wave functions. Wave functions containing up to 220 terms have been used, and the least accurate f value is estimated to be correct to within +0.0002, an accuracy sufficient for all practical applications.

Scientific legacy of Robert L. Platzman. Preliminary report

“…A highlight is the result that the oscillator strength of the strongest line, i. e., for the 21P excitation, is about 0.277, as announced in a related published paper (Miller and Platzman, 1957). This value agrees closely with 0.2762, the result of a highly reliable calculation by Schiff and Pekeris (1964).…”

Inelastic scattering of high energy electrons by atmospheric gases

“…The experimental value obtained in this way at 25 keV is 0.312 + 0.040. This is to be compared to the theoretical value 0.2762 which is known to be accurate (80). An experimental value (131) of 0.27 + 0.02 has recently been determined.…”

“…have studied the 1's -> 2lP transition in helium. The data were fitted with a semi-theoretical formula and normalized by requiring that the limit of the generalized oscillator strength (at zero momentum change) be equa: to the optical oscillator strength calculated by Schiff and Pekeris (80). Several kinetic energies were employed in the range (100400 eV) and curves of oscillator strength vs. square of momentum change were coincident at kinetic energies of 200 eV and higher.…”

A b i n i t i o CI calculation of the vibrational structure of the 1(nπ*) transition in formaldehyde

“…This is a fact well known in the very few calculations that have so far been done with the acceleration formula. [28][29][30][31] It turns out that the acceleration formula depends very sensitively upon the wave function close to the nuclei, because of the 1/ r 2 term in the operator. 32 The dipole length form of the transition moment depends more strongly on the wave function farther from the nuclei; therefore, So comparing the acceleration and length moments gives an estimate of the accuracy of the electric field transition components.…”