Nature of the excited states of He$sub 2$

Journal Article · Wed Oct 01 04:00:00 EDT 1975 · Phys. Rev., A, v. 12, no. 4, pp. 1203-1221

OSTI ID:4150035

Guberman, S L; Goddard, III, W A

The low-lying excited states of He$sub 2$ have been examined using spatially projected generalized-valence-bond wave functions. Typically the excited-state potential curves are repulsive at large R (internuclear distance) but exhibit an attractive well at small R. We find that the repulsion at large R results from an unfavorable exchange interaction of a Rydberg orbital mostly on one He with the two core orbitals on the other He. This arises from the restrictions on the molecular wave function implicit in the Pauli principle and is similar in nature to the repulsive pair-pair interactions between ground-state He atoms. For R < 3a$sub 0$ the Rydberg orbital is large compared with R and the shape of the potential curve is determined by core-core interactions. For the A $sup 1$$Sigma$/subu/$sup +$ state, the calculated maximum in the potential curve is 0.0607 eV at 3.09 A, in excellent agreement with experimentally derived values. Results are presented for several other excited states.

• Research Organization: Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125
• NSA Number: NSA-33-003963
• OSTI ID: 4150035
• Journal Information: Phys. Rev., A, v. 12, no. 4, pp. 1203-1221, Journal Name: Phys. Rev., A, v. 12, no. 4, pp. 1203-1221; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

*HELIUM-- EXCITED STATES
640302* --Physics Research--Atomic
Molecular &amp; Chemical Physics--Atomic &amp; Molecular Properties
N60200* --Physics (Atomic &amp; Molecular)--Atomic &amp; Molecular Properties
PAULI PRINCIPLE
RYDBERG CORRECTION
WAVE FUNCTIONS