Is there a choice between diabatic and adiabatic representations of coupled Schrödinger equations in WavePacket?
Internally, WavePacket is using a diabatic representation throughout, i.e. the dynamics of the wavefunctions are coupled to each other through matrix valued potentials and/or transition dipole moments interacting with external fields (but not through kinetic/derivative coupling). Accordingly, all Matlab potential and dipole functions have to be written such that they return (real, symmetric) diabatic potential and dipole matrices for each grid point in position space. However, if desired the output of expectation values and generation of animated wavepackets can be transformed to the adiabatic representation by changing the variable space.representation (4.5. hamilt.coupling.representation) in the input data file initialize.m from ‘dia’ to ‘adi’. Moreover, there is also a choice (variable psi.init.representation) in the input data file, whether the initial populations (vector psi.init.coeffs) refer to diabatic or adiabatic states.
