Long-range interatomic dipoles

✍ Scribed by W. Byers Brown; D.M. Whisnant

• Publisher: Elsevier Science
• Year: 1970
• Tongue: English
• Weight: 369 KB
• Volume: 7
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(70)80174-9

✦ Synopsis

A new formula is presented for the coefficient D'/ of the leading term in Rw7 for the electric dipole moment of two atoms in S-states at a large distance R apart. An approximation is proposed which leads to a simple formula for D7 involving mainly accessible atomic properties. The approximation is checked for scaled hydrogen atoms and is accurate to about one per cent. -1. INTRODUCTION When two dissimilar atoms interact they possess an electric dipole moment. This is the origin of the collision-induced absorption (CIA) spectra of rare-gas mixtures in the far infrared first observed by Kiss and Welch [l] in 1959. The complete absorption bands for He-Ar and Ne-Ar were first seen by Bosomworth and Gush [Z], but for He-Ne the absorption was too weak to be observed. These experiments led to a lot of theoretical work concerned with developing an adequate theory of the absorption [3-51, with calculating the interaction dipole-moment function ,u(R) from molecular quantum mechanics [6-8] and with putting the two together [9] or in other ways deriving information about /J(R) from the CL4 experiments [lo, 111.

For two S-state atoms which do not overlap the interaction dipole is due to inter-electron correlation of the kind which leads to the attractive dispersion