Charge asymmetry in pure vibrational states of the HD molecule

摘要

Very accurate variational calculations of all rotationless states (also called pure vibrational states) ofthe HD molecule have been performed within the framework that does not assume the Born–Oppenheimer (BO) approximation. The non-BO wave functions of the states describing the internalmotion of the proton, the deuteron, and the two electrons were expanded in terms of one-centerexplicitly correlated Gaussian functions multiplied by even powers of the internuclear distance. Upto 6000 functions were used for each state. Both linear and nonlinear parameters of the wavefunctions of all 18 states were optimized with a procedure that employs the analytical gradient of theenergy with respect to the nonlinear parameters of the Gaussians. These wave functions were usedto calculate expectation values of the interparticle distances and some other related quantities. Theresults allow elucidation of the charge asymmetry in HD as a function of the vibrationalexcitation.