Intermolecular interactions in a radiation field via the method of induced moments

Journal Article · Sun Jan 15 04:00:00 EST 2006 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.73.0· OSTI ID:20786735

Salam, A ^[1]

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1. Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina 27109-7486 (United States)

Molecular quantum electrodynamics is employed to calculate a generalized formula for the energy shift between a pair of molecules that have electric polarizability of arbitrary multipole order and are in the presence of an intense electromagnetic field. In contrast to a previous calculation of the dipole-dipole contribution, which required fourth-order time-dependent perturbation theory for its evaluation, the present approach involves calculating the interaction between the multipole moments induced at each center by the incident beam and the resonant multipole-multipole coupling tensor together with the average value of the spatial correlation function of the displacement field for an N-photon state. The theory developed applies to the situation where the molecular pair is held fixed relative to the direction of propagation of the radiation field or is allowed to be completely randomly oriented. Explicit results are obtained for dipole-quadrupole and quadrupole-quadrupole polarizable molecules. For oriented systems the energy shift for linear and circular polarizations is examined for incident radiation propagating in directions parallel and perpendicular to the intermolecular join, and the asymptotic behavior is obtained at the limits of short and large separation distance. After performing a pair orientation average, the energy shift in the near zone is found to exhibit an R{sup -1} power-law behavior with separation distance, while the far zone has a modulated R{sup -2} dependence in all of the cases considered. None of the energy shifts obtained display discriminatory characteristics, with respect to either the handedness of the incident beam or the individual species.

• OSTI ID: 20786735
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 1 Vol. 73; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
CORRELATION FUNCTIONS
COUPLING
DIPOLES
ELECTROMAGNETIC FIELDS
EVALUATION
MOLECULES
ORIENTATION
PERTURBATION THEORY
PHOTONS
POLARIZABILITY
POLARIZATION
QUADRUPOLES
QUANTUM ELECTRODYNAMICS
TENSORS
TIME DEPENDENCE