ISSN:
1434-6079
Keywords:
31.20.D
;
31.50
;
34.30
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract Potential energy surfaces for the collision of He atoms with NH radicals in the electronically excitedA 3 Π state have been calculated using quantum chemical ab initio methods. The NH distance was kept fixed to its equilibrium value, the range of the HN-He distancesR and HNHe angles γ was chosen to be 4.0≦R≦8.0a 0, 0≦γ≦180°. The doubly degenerate NH(A 3 Π) state is split upon approach of He into two components, 13 A′ and 23 A″, which remain degenerate only for collinear geometries. The resulting two potential surfacesV A′ andV A″ are essentially repulsive with shallow van der Waals minima at large distances. An expansion of the sum and the difference potential,V A′ +V A″ andV A′ −V A″, respectively, in terms of Legendre polynomials shows that the anisotropic componentsV 10(R) andV 22(R) which mainly govern rotational transitions and Λ-doublet mixing are of the same size. It is therefore expected that these processes as well as fine-structure transitions are similarly probable in NH(A 3 Π)-He collisions. This is in accord with recent experiments of Kaes and Stuhl.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01399036
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