Eigenspectra calculations using Cartesian coordinates and a rotational symmetry adapted lanczos method

摘要

An efficient method is presented for performing moleuclar quantum dynamics calculations using the (3-f-3)Cartesian components of the (f-1)Jacobi vectors,where f is the number of atoms Coriolis coupling is treated exactly,but with two extra degrees of freedom,relative to coordinates that explicitly separate rotatin from vibration.On the ohter hand,the Cartesian approach has several appealing advantages:(1)code scalability,(2)simple kinetic energies,and (3)minimal CPU requirements (for a given basis size).Our approach combines the phase space optimized discrete variable representation method,which mitigates the effect of the larger dimenslity,together with a version of the symmetry adapted Lanczos method that can exploit both rotational and permutation-inversion symmetry to reduce the effective level degeneracy,adn the required number of Lanczos iterations.Results are proesnted for a three-dimensional calculation of the bound rovibrational levesl of the neon dimer.