Hi QChem Forum,

can anyone define the difference between the calculated Transition Moment and Transition Dipole Moment (in the Excited State Analysis) when one does a TD-DFT calculation? It is not a simple unit conversion and when those quantities are discussed in the literature they seem to be used quite synonymously. Every input or link to proper literature would be greatly appreciated. The output in question looks as follows:

Excited state 2: excitation energy (eV) = 2.4820

Total energy for state 2: -5641.73302437 au

Multiplicity: Singlet

Trans. Mom.: 0.1811 X 0.0234 Y 0.0383 Z

Strength : 0.0021162303

X: D( 437) → V( 2) amplitude = 0.3114

X: D( 441) → V( 1) amplitude = 0.9308## Singlet 2 :

`CT numbers (Mulliken) omega = 1.0222 <Phe> = -0.1050 Exciton analysis of the transition density matrix Trans. dipole moment [D]: 0.237087`

Cartesian components [D]: [ -0.230112, -0.029764, -0.048712]

Thank you

Sara