Novel theory of the HD dipole moment. I. Theory

Journal Article · Tue Jan 01 04:00:00 EST 1985 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.31.22· OSTI ID:5987761

Thorson, W R; Choi, J H; Knudson, S K

A novel theory of the electric dipole moments of homopolar but isotopically asymmetric molecules (such as HD, HT, or DT) is formulated, such that electrical asymmetry and the resulting dipole moment arise as purely electronic properties within a suitable Born-Oppenheimer approximation, and nonadiabatic (rovibronic) perturbations play no part in the theory. It is shown thereby that a much simpler and more direct explanation for these dipole moments can be given than that invoking non- adiabatic perturbations: The dipole moment arises from isotopic variation of the local effective electronic reduced mass and its effects on binding energies and sizes of orbitals. It is an odd function of the isotopic splitting parameter ..cap alpha../sub 0/ = (1/2)lambdam/..mu.., where lambda = (M/sub A/-M/sub B/)/(M/sub A/+M/sub B/) is the nuclear mass asymmetry for nuclei A,B and (m/..mu..) is the electron-nuclear mass ratio (for HD, this parameter is 1.36 x 10/sup -4/). A canonical transformation exhibiting these effects (in the form of an asymmetric effective potential) is the basis for the new formulation. Since ..cap alpha../sub 0/ is small the resulting dipole moment function is essentially linear in ..cap alpha../sub 0/, and hence the dipole moment functions for HT and DT may be computed by rescaling the results for HD. Since the problem is purely electronic in the new formulation, variational and convergence studies are easy to carry out. In this and the following paper we formulate the new theory in detail and carry out variation-perturbation calculations of the HD dipole moment.

• Research Organization: Department of Chemistry, The University of Alberta, Edmonton, Alberta, Canada T6G2G2
• OSTI ID: 5987761
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Journal Issue: 1 Vol. 31:1; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ASYMMETRY
BINDING ENERGY
COMPARATIVE EVALUATIONS
DEUTERIDES
DEUTERIUM COMPOUNDS
DIPOLE MOMENTS
EFFECTIVE MASS
ELECTRIC DIPOLE MOMENTS
ELECTRIC MOMENTS
ENERGY
HYDROGEN COMPOUNDS
HYDROGEN DEUTERIDE
HYDROGEN TRITIDE
ISOTOPE EFFECTS
LABELLED COMPOUNDS
MASS
PERTURBATION THEORY
TRITIUM COMPOUNDS
VARIATIONAL METHODS