A practical method for the use of curvilinear coordinates in calculations of normal-mode-projected displacements and Duschinsky rotation matrices for large molecules

摘要: While use of curvilinear coordinates such as bond lengths and angles is common in accurate spectroscopic and/or scattering calculations for triatomic other small molecules, their large molecules uncommon restricted. For normal-mode analysis feasible but gives sensible results only if the dynamical or process being considered involves changes angular coordinates, including ring deformations, which are so that motion can be approximated by its tangential component. We describe an approximate method normal-mode-projected displacements hence Franck–Condon factors, reorganization energies, vibronic coupling constants, well Duschinsky (Dushinsky, Duschinskii) rotation matrices, evaluated systems. Three illustrative examples provided: (i) to understand nature first excited state water, illustrating properties large-amplitude bending motions; (ii) “boat” relaxation pyridine, torsional (iii) vibrational modes oxidation bacteriochlorophyll-a, a paradigm with many applications both chemical biological electron transfer, macrocyclic deformations. The interfaced wide variety computational chemistry computer programs.