Here µ is the electronic transition dipole moment along the ρ or ξ cartesian axis, P i is the Boltzmann thermal occupation of vibrational state |i⟩, and H g and H e are the ground and excited state vibrational Hamiltonians. In turn, the inhomogeneous broadening function, G(ω eg ), is expressed as a normalized distribution of 0-0 energies around an average energy ωeg