rraman.getBrownianDamping

rraman.getBrownianDamping(t, kappa, T, egamma, cutoff=1e-06)

Calculate the damping term using Mukamel’s Brownian oscillator model based on Myers Fortran code. The real part of g(t) leads to a Gaussian broadening of the spectra, while the imaginary part leads to a solvent induced Stokes shift.

Parameters:
  • t (array) – Time axis (fs).
  • kappa (float) –

    Lineshape parameter:

    • kappa >> 1 = Lorentzian,
    • kappa << 1 = Gaussian.
  • T (float) – Temperature in K.
  • egamma (float) – Electronic homogeneous linewidth (FWHM, cm-1).
  • cutoff (float) – Cutoff for sum over Brownian oscillators. Typically between 1e-6 (default) and 1e-8. Check for convergence by re-running with different values.
Returns:

Damping term in the time domain, e^{-g(t)}.

See also

Myers, J. Raman. Spectrosc. 28, 389 (1997)