Improvement in the First Born Theory of Electron Scattering by Molecular Systems. II. Example of the1sσg−2pσu

Abstract

The form of Eq. (8) is known to be incorrect for dissociation states when discussing certain differential cross sections but is satisfactory for computing the total cross section. See T. A. Green and J. M. Peek, Phys. Rev. Letters 21, 1734(1968).

Low-energy electron-impact dissociative excitation of molecular hydrogen and its isotopologues

“…This method has been applied to dissociative processes in a number of previous works [20, 26-28, 33, 34], yielding results in good agreement with experiment. Peek and Green [35,36] showed that the standard AN method is sufficiently accurate for the dissociative 1sσ g → 2pσ u transition in H + 2 at intermediate to high energies.…”

Calculations of electron scattering from H2+

“…Expression (8) averages the cross sections over the initial vibrational wave function of the molecule but does not retain energy conservation between vibrational state transitions. This has been shown to be accurate outside the low-energy region for H 2 + [20]. To compare with experiment we weight cross sections of the bound H 2 + vibrational levels viã…”

“…These methods compared well with experimental PP and DI data at high energies. Peek and Green [20] validated closure methods (summing cross sections over final rotationalvibrational states) in the Born approximation for H 2 + . The distorted-wave method of Robicheaux [21] utilized the fixed-nuclei approximation to calculate DI cross sections.…”

Nonlinear optical characteristics of 3-methoxy-4-hydrobenzaldehyde crystals

“…The random errors are 90% confidence limits at each energy. Figure 1 illustrates these results and compares them with theoretical values obtained from the work of Peek (1967), and Peek and Green (1969). The latter paper gives cross Franck-Condon factors were taken from unpublished work by Peek but they are essentially identical to those presented by Villarejo (1968).…”

“…These were made by the coincident detection of protons and hydrogen atoms formed by dissociative excitation. It was of paramount importance to specify the initial excitation of the H; beam because Peek and Green (1969) and others (see I) have predicted that G~ differs by three orders of magnitude for the various vibrational states of H l . Paper I includes a description of a novel ion source which was designed to fulfil criteria suggested by Dunn and Van Zyl.…”