  Quantum chemical calculations of one-photon absorption, electronic circular
dichroism and anisotropy factor spectra for the A-band transition of fenchone,
camphor and 3-methylcyclopentanone (3MCP) are reported. While the only weakly
allowed nature of the transition leads to comparatively large anisotropies, a
proper theoretical description of the absorption for such a transition requires
to account for non-Condon effects. We present experimental data for the
anisotropy of 3MCP in the liquid phase and show that corresponding
Herzberg-Teller corrections are critical to reproduce the main experimental
features. The results obtained with our comprehensive theoretical model
highlight the importance of the vibrational degree of freedom, paving the way
for a deeper understanding of the dynamics in electronic circular dichroism.
