We perform calculations using the semiclassical Fourier approach for quasimolecular spectra induced by thermal collisions of the excited calcium atom (Ca*) with the helium atom in the ground state (He) for the following quasimolecular optical transitions: (Ω = 0+, 4s4p 1P) ↔ (Ω = 0+, 4s2 1S0) and (Ω = 0+, 4s3d 1D) ↔ (Ω = 0+, 4s2 1S0) in the Ca-He quasimolecule. As a comparison with the experimental results obtained under gas-cell conditions, we average the spectra under study over the impact parameters and the Maxwellian distribution of the colliding particles. For the asymptotically forbidden Ca(4s2 1S0 → 4s3d 1D2)-He quasimolecular transition, the first comparison between the calculated spectral line profile and the experimental one is made not only in shape, but also in absolute value. We clarify the physical mechanisms for the initiation of a spectral line satellite at the position of the forbidden atomic transition being investigated. The reasonable agreement confirms that the spectral lineshapes of the asymptotically forbidden transitions are formed due to the interplay between the structure of the potential energy curves involved and the strong dependence of the radiative width.
|Number of pages||12|
|Journal||Journal of Physics B: Atomic, Molecular and Optical Physics|
|Publication status||Published - 2001 Jun 28|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics