Quantum mechanical calculation of the OH vibrational frequency in crystalline solids - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Molecular Physics Année : 2005

Quantum mechanical calculation of the OH vibrational frequency in crystalline solids

Résumé

The OH vibrational frequency of four crystalline compounds ranging from ionic (brucite, Mg(OH)2, and portlandite, Ca(OH)2) to semi-covalent (edingtonite, as representative of free surface OH groups in silica, and acid chabazite, as representative of acid zeolites) has been investigated at quantum mechanical level with the CRYSTAL program using the B3LYP hybrid functional. The OH vibration is calculated in two ways: (i) in the harmonic approximation, by diagonalizing the fully coupled dynamical matrix to yield the harmonic frequency ω h . (ii) at the anharmonic level, by decoupling the OH stretching mode from the bulk phonons and by numerically solving the one-dimensional Schrödinger equation associated with the OH potential energy to yield the fundamental ω01 and the first overtone ω02 frequencies. The harmonic and anharmonic frequencies differ by more than 150 cm−1. In the cases where direct comparison is possible (brucite, portlandite and edingtonite), the experimental and calculated frequencies differ by less than 10 cm−1; the calculated anharmonicity constant, ω e x e  = (2ω01 − ω02)/2, is systematically smaller than the experimental value by about 10 cm−1. The effect of the computational parameters on the computed frequencies is explored, with particular attention to the grid used for the construction of the DFT exchange and correlation contribution to the Hamiltonian and the accuracy in the geometry optimisation.
Fichier non déposé

Dates et versions

hal-01891688 , version 1 (09-10-2018)

Identifiants

Citer

S. Tosoni *, Fabien Pascale, P. Ugliengo, R. Orlando, R. Saunders, et al.. Quantum mechanical calculation of the OH vibrational frequency in crystalline solids. Molecular Physics, 2005, 103 (18), pp.2549 - 2558. ⟨10.1080/00268970500180808⟩. ⟨hal-01891688⟩
13 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More