A quantum-mechanical study of the reaction H+HF( vjm j)→HF( v′j′m′ j)+H: Exact and centrifugal decoupling calculations in hyperspherical coordinates

Abstract

Three-dimensional close-coupling calculations in hyperspherical coordinates have been performed for the reaction H+ HF( vjm j )→HF( v′j′m′ j )+H at energies below the vibrational threshold v=2 of HF and at non-zero total angular momentum ( J=2). Exact calculations using a space-fixed frame are compared with approximate ones involving centrifugal decoupling in a body frame tied to the principal axes of inertia. The decoupling method accurately reproduces the individual reaction probabilities, especially at low collision energy. The dense resonance spectrum appearing in the exact results is reproduced with a hyperspherical model which neglects centrifugal and non-adiabatic couplings and affords a systematic classification of the resonances.