Studies of molecular Rydberg states by Schwinger variational-quantum defect methods: Application to molecular hydrogen

Journal Article · Mon Nov 30 23:00:00 EST 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.463428· OSTI ID:7198540

Stephens, J A; McKoy, V ^[1]

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1. Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125 (United States)

An {ital ab} {ital initio} electronic structure technique has been developed to study highly excited states of molecules by combining Schwinger variational methods of collision theory with generalized quantum defect theory. The technique exploits methods of scattering theory to study the region of highly excited Rydberg levels below and across ionization thresholds for molecules. The reaction matrix {ital K}, which describes the interaction of the Rydberg electron with the ionic core, is found at arbitrary negative electron energies by employing an unbounded Coulomb Green's function in the Lippmann--Schwinger equation for the electronic wave function. Quantal conditions are imposed to obtain discrete molecular energy levels, associated Rydberg wave functions, and quantum defect functions, all as a function of the internuclear distance. Results within the static-exchange approximation for the {sup 1,3}{Sigma}{sup +}{sub {ital u}}(1{sigma}{sub {ital g}n}{sigma}{sub {ital u}}) and {sup 1,3}{Pi}{sub {ital u}}(1{sigma}{sub {ital g}n}{pi}{sub {ital u}}) Rydberg states of H{sub 2}, for {ital n}=2--20 and {ital R}=1.2--5.0 {ital a}{sub 0}, are presented and discussed.

• OSTI ID: 7198540
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 97:11; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

664100 -- Theory of Electronic Structure of Atoms & Molecules-- (1992-)
664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
COULOMB FIELD
DISTANCE
ELECTRIC FIELDS
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY
ENERGY LEVELS
EQUATIONS
EXCITED STATES
FUNCTIONS
GREEN FUNCTION
HYDROGEN
INTEGRAL EQUATIONS
INTERATOMIC DISTANCES
IONIZATION
LIPPMANN-SCHWINGER EQUATION
MOLECULES
NONMETALS
RYDBERG STATES
SCHWINGER VARIATIONAL METHOD
THRESHOLD ENERGY
VARIATIONAL METHODS
WAVE FUNCTIONS