Rigid Body Approximation for the Anharmonic Description of Molecule–Surface Vibrations
| Autor: | Marcin Rybicki, Joachim Sauer |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Journal of Chemical Theory and Computation. 18:5618-5635 |
| ISSN: | 1549-9626 1549-9618 |
| Popis: | We present an anharmonic approach for molecule-surface vibrations that employs rigid body coordinates, based on the Rodrigues rotation formula, to describe curvilinear displacements (rotations and translations) of the molecule along normal modes. These displacements are used to calculate energy data points from which one-dimensional polynomial potentials are fitted using cubic splines. In these potentials, for each of the six rigid body modes separately, one-dimensional Schrödinger equations are solved with harmonic oscillator or Fourier functions (for pure rotations) as basis sets. The anharmonic vibrational energies obtained are used to calculate partition functions and from them enthalpies, entropies, and Gibbs free energies of adsorption. Our numerical implementation has been successfully tested for Morse and cosine potentials with known analytical solutions. The methods have been applied to adsorption of CH |
| Databáze: | OpenAIRE |
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