Ultraviolet cavity ringdown spectra and the S1(n,pi) ring-inversion potential energy function for 2-cyclohexen-1-one-d0 and Its 2,6,6-d3 isotopomer.

The cavity ringdown spectra of 2-cyclohexen-1-one (2CHO) and its 2,6,6-d3 isotopomer (2CHO-d3) have been recorded in the spectral region near their S1(n,pi)<--S0 band origins which are at 26,081.3 and 26,075.3 cm-1, respectively. The data allow several of the quantum states of nu39, the ring inversion, to be determined for both the ground and excited electronic states. These were utilized to calculate the one-dimensional potential energy functions which best fit the data. The barriers to inversion for the S0 and S1(n,pi) states were found to be 1,900 +/- 300 and 3,550 +/- 500 cm-1, respectively. Density functional theory calculations predict values of 2,090 and 2,265 cm-1, respectively.