-? T* transitions; however, the existence of lower energy singlet n,? r* states is predicted. Neither isomer undergoes photoisomerization in the solid state. Photoisomerization of the E isomer is efficient in nonpolar solvents but occurs with decreased efficiency in solvents which are good hydrogen bond acceptors. The Z isomer undergoes photoisomerization only in strong hydrogen bond acceptor solvents which disrupt the intramolecular hydrogen ...