Vibrational Frequency Shift (1st Order)

Available identifiers

frequency shift of molecular vibrations caused by interaction with surrounding particles from 1st order non-degenerate perturbation theory

Description

The interpretation is quite straight-forward: Effectively, the intermolecular potential changes the effective force constant of a vibrational normal mode.

Defining Formula: $E_{1, r}^{(1)} - E_{0, r}^{(1)} = \frac{1}{2} \frac{\partial^{2} U}{\partial q_{r}^{2}}$
$E$ symbol represents Quantum Eigen Energy
$U$ symbol represents Intermolecular Potential
$q$ symbol represents Normal Mode Coordinate (Dimensionless)