Results are presented from extensive ab initio calculations on several low-lying singlet states of cis- and trans-1,3-butadiene. The results indicate a qualitative difference between the cis and trans isomers for the lowest π → π* transition. For the cis isomer, the first excited singlet state of the same symmetry as the ground state is found to lie above the lowest π → π* transition, and we estimate that this is also the case for the trans isomer.
© 1987 American Chemical Society
Cave, R.J.; Davidson, E.R. “A theoretical investigation of some low-lying singlet states of 1,3-butadiene,'' J. Phys. Chem. 1987, 91, 4481-4490. doi: 10.1021/j100301a013