Computations of Vibron Excitations and Raman Spectra of Solid Hydrogens

Abstract

Numerical calculations for the vibronic states in the mixed ortho-para solid hydrogens are reviewed. They were performed within the supercell method on the basis of the Van Kranendonk theory and the Raman spectra were calculated and compared with experiment. Anderson localization is a feature of the results especially in the Raman scattering region of frequencies and especially when the ortho-para mixture is substantial. A simple approximate Hamiltonian model has been used and is surprisingly useful, leading to a suggestion that at high pressures the high frequency peak of the vibron spectrum of a mixed system is due to anisotropic Raman scattering from the ortho (para) hydrogen (deuterium) molecules, even under the assumption that the orbital angular momenta are disoriented.