Ab initio quantum-mechanical simulation of the Raman spectrum of grossular
Résumé
The Raman spectrum of the grossular garnet Ca3Al2Si3O12 has been simulated with the periodic ab initio CRYSTAL code by adopting an all-electron Gaussian-type basis set and the B3LYP Hamiltonian. The wavenumbers of the 25 Raman active modes (3 of A1g, 8 of Eg and 14 of F2g symmetry) are in excellent agreement with two sets of accurate experimental data. Isotopic substitution is used to measure the participation of Ca and Si (Al is constrained in a centro-symmetric position) to the various modes.