Collisional Excitation Transfer of SP Type Between Identical Atoms
Abstract
The electronic excitation transfer cross section between identical atoms in S and P states in the gas phase was investigated theoretically in the lowincidentenergy range by means of the impactparameter method. With respect to the P states of an atom, all three degenerate P states of mutually orthogonal polarizations were taken into account. The direction of P polarization was taken into account using two different methods. These methods were the "fixedatom approximation" and the "rotatingatom approximation," respectively. The difference between the solution from coupled equations with respect to the direction of Pstate polarization and those from the respective approximations mentioned above was studied. The fixedatom approximation was found to be better than the rotatingatom approximation for the computation of the overall cross section of SPtype excitation transfer. The cross section obtained from the coupled equations was nearly onehalf of that from the rotatingatom approximation and nearly 1.5 times as much as that from the fixedatom approximation. It is shown that the total cross section can be written as σ=3.36πe^{2}μ^{2}ℏv, where v represents the relative velocity of an incident atom, e the electronic charge, and μ the transition dipole matrix element between the S and P states under consideration.
 Publication:

Physical Review
 Pub Date:
 June 1965
 DOI:
 10.1103/PhysRev.138.A1573
 Bibcode:
 1965PhRv..138.1573W