[ital Ab] [ital initio] complex Kohn calculations of dissociative excitation of methane: Close-coupling convergence studies

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.49.2551· OSTI ID:5120141

Gil, T J; Lengsfield, B H; McCurdy, C W; Rescigno, T N ^[1]

---

1. Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

Results of close-coupling calculations using the complex Kohn method are reported for excitation of the methane molecule into electronically dissociative states. The excited states in question are of Rydberg nature and are classified by analogy with the isoelectronic Ne atom as 2[ital p][r arrow]3[ital s], 2[ital p][r arrow]3[ital p], and 2[ital p][r arrow]3[ital d] transitions, i.e., single excitations of the valence 2[ital p] electron into the [ital n]=3 Rydberg manifold. On the basis of optical selection rules, one expects large excitation probabilities to analogues of [sup 1][ital P] odd-parity states. Our calculations in the energy range 11--60 eV show a more complex picture of the excitation dynamics and detect large excitation probabilities for triplet and even-parity (2[ital p][r arrow]3[ital p]) states. A similar result is obtained for the excitation of the Ne atom. Although, to the authors's knowledge, these are the largest close-coupling electron--polyatomic-molecule scattering calculations to date, the results lead to questions concerning the convergence of the close-coupling approach in the case of Rydberg-state excitation. Conclusions are drawn in the context of earlier results for electron-impact excitation of the H, He, and Ne atoms.

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5120141
• Journal Information: Physical Review A; (United States), Journal Name: Physical Review A; (United States) Vol. 49:4; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

664300* -- Atomic & Molecular Physics-- Collision Phenomena-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ALKANES
CALCULATION METHODS
COLLISIONS
DISSOCIATION
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
ELEMENTS
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EV RANGE
EV RANGE 10-100
EXCITATION
EXCITED STATES
FLUIDS
GASES
HYDROCARBONS
METHANE
MOLECULE COLLISIONS
NEON
NONMETALS
ORGANIC COMPOUNDS
RARE GASES
RYDBERG STATES
SELECTION RULES
VARIATIONAL METHODS