Pressure broadening and shift of He(2 {sup 3}P{sub 0,1,2})-He(2 {sup 3}S) lines
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138 (United States)
The collisional broadening and shift of metastable helium fine-structure lines are calculated within the impact approximation. Ab initio Born-Oppenheimer potential energy curves correlating to He(1 {sup 1}S{sub 0}) and He(2 {sup 3}P{sub j}) atomic levels are obtained using the configuration interaction valence bond method and combined with semiempirically calculated van der Waals interaction terms between these atoms to also study j-specific and j-changing collisions. A long-range van der Waals potential well exists in the {sup 3}{pi}{sub u} potential correlated to the He(1 {sup 1}S{sub 0})+He(2 {sup 3}P{sub j}) limit, whose influence on the scattering phase shift is assessed. At T=310 K, the broadening and shift parameters are practically j independent and have average values of 12.60 and 1.87 MHz/Torr, respectively. The j-changing collisions have cross sections roughly five times smaller than the j-specific cross sections.
- OSTI ID:
- 20640737
- Journal Information:
- Physical Review. A, Vol. 69, Issue 2; Other Information: DOI: 10.1103/PhysRevA.69.022714; (c) 2004 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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