Vibrational Frequency Shift (2nd Order)

Available identifiers

MaRDI QIDQ6674549

frequency shift of molecular vibrations caused by interaction with surrounding particles from 2nd order non-degenerate perturbation theory

Description

The interpretation is based on the coupling of different vibrational normal modes, mediated by the cubic anharmonicity of the intramolecular force field.

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Defining Formula: $E_{1,r}^{(2)}-E_{0,r}^{(2)}=\frac{1}{2}\frac{{\varphi }_{rrs}}{{\omega }_s}\frac{\partial U}{\partial q_s}$

$E$ symbol represents Quantum Eigen Energy

$U$ symbol represents Intermolecular Potential

$\omega$ symbol represents Vibration Frequency (Harmonic)

$\varphi$ symbol represents Force Constant (Anharmonic)

$q$ symbol represents Normal Mode Coordinate (Dimensionless)

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