LAMBDA -doublet population inversion in collisions of OH, OD, CH, CD and NH+.
Abstract
A scattering-theory approach is used to study collisional mechanisms of Lambda-doublet population inversion in OH, CH, OD, CD, and NH(+) for collisions of H, H2, He, H(+), and H3(+) with the diatomics in their rotational ground states. It is assumed that exchange forces between two open-shell collision partners impart a strong anisotropy to the interaction potential, so that collisions with H atoms have larger cross sections than those with H2 and, in some cases, may lead to opposite Lambda-doublet behavior. Implications of the results for maser action are discussed qualitatively, and inversion in OH and CH is considered in detail. Predictions are made concerning the feasibility of observing OD, CD, and NH(+) in radio emission.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- November 1979
- DOI:
- 10.1093/mnras/189.3.583
- Bibcode:
- 1979MNRAS.189..583D
- Keywords:
-
- Hydrocarbons;
- Hydroxyl Emission;
- Interstellar Masers;
- Ionic Collisions;
- Nitrogen Hydrides;
- Optical Pumping;
- Population Inversion;
- Abundance;
- Far Infrared Radiation;
- Fine Structure;
- Inelastic Collisions;
- Molecular Excitation;
- Scattering Cross Sections;
- Wave Functions;
- Astrophysics;
- Masers