Here, the electronic-vibrational component is calculated the same as previously (Equations 42 and 43), however the electronic-nuclear component is calculated using modern quantum chemical techniques . Specific examples can be found within density functional theory, such as the method developed by Chernyak & Mukamel building on the work of Send & Furche . Outside of density functional theory, the couplings could be computed directly using a state-averaged gradient within a multi-configurational based method .