Bubin, SergiyStanke, MonikaAdamowicz, Ludwik2016-01-292016-01-292011Sergiy Bubin, Monika Stanke, Ludwik Adamowicz; 2011; Complete pure vibrational spectrum of HD calculated without the Born-Oppenheimer approximation and including relativistic corrections; PHYSICAL REVIEW Ahttp://nur.nu.edu.kz/handle/123456789/1082All 18 bound pure vibrational levels of the HD molecule have been calculated within the framework that does not assume the Born-Oppenheimer (BO) approximation. The nonrelativistic energies of the states have been corrected for the relativistic effects of the order of α2 (where α is the fine structure constant), calculated using the perturbation theory with the nonrelativistic non-BO wave functions being the zero-order approximation. The calculations were performed by expanding the non-BO wave functions in terms of one-center explicitly correlated Gaussian functions multiplied by even powers of the internuclear distance and by performing extensive optimization of the Gaussian nonlinear parameters. Up to 10 000 basis functions were used for each stateenAttribution-NonCommercial-ShareAlike 3.0 United StatesResearch Subject Categories::NATURAL SCIENCES::PhysicsHD moleculeBorn-Oppenheimer approximationArticle