ROTATIONAL QUENCHING OF ROTATIONALLY EXCITED H{sub 2}O IN COLLISIONS WITH He
- Department of Physics and Astronomy and the Center for Simulational Physics, University of Georgia, Athens, GA 30602 (United States)
Theoretical rotational quenching cross sections and rate coefficients of ortho- and para-H{sub 2}O due to collisions with He atoms are presented. The complete angular momentum close-coupling approach as well as the coupled-states approximation for the angular momentum decoupling was applied to solve the scattering problem for a large range of rotationally excited states of water. Results are obtained for quenching from initial levels 1{sub 1,0}, 2{sub 1,2}, 2{sub 2,1}, 3{sub 0,3}, 3{sub 1,2}, 3{sub 2,1}, 4{sub 1,4}, 3{sub 3,0}, and 4{sub 2,3} of ortho-H{sub 2}O and from initial levels 1{sub 1,1}, 2{sub 0,2}, 2{sub 1,1}, 2{sub 2,0}, 3{sub 1,3}, 3{sub 2,2}, 4{sub 0,4}, 4{sub 1,3}, and 3{sub 3,1} of para-H{sub 2}O for kinetic energies from 10{sup -5} to 10{sup 4} cm{sup -1}. State-to-state and total deexcitation cross sections and rate coefficients for temperatures between 0.1 and 3000 K are reported. The present state-to-state rate coefficients are found to be in good agreement with previous results obtained by Green and coworkers at high temperatures, but significant discrepancies are obtained at lower temperatures likely due to differences in the adopted potential energy surfaces. Astrophysical applications of the current rate coefficients are briefly discussed.
- OSTI ID:
- 22127028
- Journal Information:
- Astrophysical Journal, Vol. 765, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Molecular beam measurements of inelastic cross sections for transitions between defined rotational states (j,m) of CsF in collisions with He, Ne, Ar, Kr, CH/sub 4/, CF/sub 4/, SF/sub 6/, C/sub 2/H/sub 6/, N/sub 2/, CO, CO/sub 2/, N/sub 2/O, CH/sub 3/Cl, CH/sub 3/Br, CF/sub 3/H, and CF/sub 3/Br
CHEMICAL COMPLEXITY IN THE HELIX NEBULA: MULTI-LINE OBSERVATIONS OF H{sub 2}CO, HCO{sup +}, AND CO