prefactor_ecd

psi4.driver.p4util.prefactor_ecd()

Prefactor for converting microscopic observable to decadic molar extinction coefficient in electronic circular dichroism.

Return type:

float

Notes

This function implements the calculation of the following prefactor:

\[k = \frac{16\pi^{2}N_{\mathrm{A}}}{3\times 1000\times \ln(10) (4 \pi \epsilon_{0}) n \hbar c^{2}}\]

The prefactor is computed in SI units and then adjusted for the fact that we use atomic units to express microscopic observables: excitation energies and transition dipole moments. The refractive index \(n\) is, in general, frequency-dependent. We assume it to be constant and equal to 1.