rraman.getCrossSections

rraman.getCrossSections(t, wn, E0, ovlps, sshift, M, IOR, damp=1, sig=0, ialpha=1)

Calculate the absorption and Raman cross-sections and the fluorescence efficiency. The latter is a unitless quantity which may be used to calculate the fluorescence rate (=rate of spontaneous emission) by integrating over the frequency axis (see Myers, Chem. Phys. 180, 215 (1994) Eq. 6 and discussion).

Note

Changed shape of input parameters and shape of return values on 10-07-2015.

Parameters:

• t (array) – Time axis in (fs). This axis is used for the calculation of the zero-zero energy term in the time domain.
• wn (array) – Wavenumber axis in (cm-1). Same shape as t.
• E0 (array) – Zero-zero energy. This function then calculates the time domain part using getZeroZeroEnergy.
• ovlps (array) – M + 2 Absorption, fluorescence and Raman overlap integrals.
• sshift (float) – Vibrational freqencies of M Raman modes to calculate (cm-1).
• M (float) – Electronic transition dipole length (A).
• IOR (float) – Index of refraction of surrounding medium / solvent.
• damp (array) – Damping function in the time domain. Same shape as t. Set to 1 if no damping is used (default).
• sig (float) – Linewidth for inhomogeneous damping (standard deviation of Gaussian), set to zero if not used (default).
• ialpha (float) –

  Lineshape parameter for inhomogeneous damping:

  • 1 = Gaussian (default),
  • 0 = Lorentzian.

Returns:

Absorption (sigmaA), M Raman cross sections (sigmaR[M]), both in A**2 / mol., and fluorescence efficiency spectrum, kF (arrays have same shape as wn); all as function of excitation wavenumber.