Electronic excitation of H sub 2 by electron impact: Close-coupling calculations using the complex Kohn variational method

• Published in: Physical review. A, Atomic, molecular, and optical physics Vol. 43:7
• Main Authors: Parker, S.D., McCurdy, C.W., Rescigno, T.N., Lengsfield, B.H. III
• Format: Journal Article
• Language: English
• Published: United States 01-04-1991
• Subjects: 640304 - Atomic, Molecular & Chemical Physics- Collision Phenomena; ATOMIC AND MOLECULAR PHYSICS; COLLISIONS; CROSS SECTIONS; DIFFERENTIAL CROSS SECTIONS; ELECTRON COLLISIONS; ELECTRON-MOLECULE COLLISIONS; ELEMENTS; ENERGY-LEVEL TRANSITIONS; EXCITATION; HYDROGEN; MOLECULE COLLISIONS; NONMETALS; SCATTERING; SMALL ANGLE SCATTERING; VARIATIONAL METHODS
• ISSN: 1050-2947; 1094-1622
• DOI: 10.1103/PhysRevA.43.3514

The complex Kohn variational method is employed in four-state close-coupling calculations to generate integral and differential cross sections for low-energy electron-impact excitation of the {sup 1}{Sigma}{sub g}{sup +}{r arrow}(b {sup 3}{Sigma}{sub u}{sup +}, {sup 3}{Sigma}{sub g}{sup +}, and {ital c} {sup 3}{Pi}{sub {ital u}}) transitions in H{sub 2}. The integral cross sections for excitation of the {sup 3}{Sigma}{sub g}{sup +} and {ital c} {sup 3}{Pi}{sub {ital u}} states from the ground state are found to be significantly different from earlier two-state calculations. The {ital a} {sup 3}{Sigma}{sub {ital g}}{sup +} cross sections are also larger than the most recent experimental results. This discrepancy is traced to the behavior of the differential cross sections at scattering angles near 0{degree} and 180{degree}, where measurements have not been carried out. The differential cross sections we find for H{sub 2} are strikingly similar to cross sections for analogous transitions in He. Previous theoretical studies of these transitions in He have also shown the two-state approximation to be inadequate.