Electric field effects on donor-acceptor dyes: A model compound study using UV/vis absorption and Raman spectroscopy

- The field of a nonconjugated charge influences polyenic Schiff base cations.
- The acceptor character increases by a positive charge near to it.
- The overall cationic charge on the conjugated system distributes more evenly.
- An energy downshift is seen for both UV-vis and Raman signals.
- Similar observations in colour vision can be rationalized.