Semi-empirical calculations of the zero-field-splitting parameters of the lowest triplet states of aromatic ketones

E.P.R. studies of the lowest excited triplet states of aromatic carbonyl molecules in mixed organic crystals

“…The assignment of the Z axis to the C=O direction is entirely consistent with these PMDR results, whereas two levels (Z and Y) should be radiatively active if the Z direction is along C-H or C-CH 3. Furthermore, the assignment of the Z axis along the C = O direction is in agreement with the predictions of the analysis of ZFS by Hayashi and Nagakura [15]. Thus, we conclude that the Z axis is approximately parallel to the C---O direction.…”

“…When the extent of the 3nTr* mixing is small (/3 ~ ~), the D and E values are given by [1,15] D--D,,+(Dn-D~)fl' [G [2 ] AE~,'…”

Isotope effects and proton hyperfine interactions in the lowest 3nπ* state of substituted benzaldehydes

“…The spin-orbit interaction will be dominated by the local symmetry of the carbonyl group and the oxygen-centered terms, so that only its z component is considered. [10][11][12][13][14] This leaves T z unperturbed in both states, but couples T x of one state with T y of the other. Approximating the vibronic sum by its first term involving the zero-point levels, the spinorbit contributions to D and E of the lower triplet state are given to lowest order by…”

“…The variations in the properties of the 3 * state have been shown to arise largely from the changing energy denominators associated with the spin-orbit and other interactions with the nearby 3n* state. [10][11][12][13][14] The details of the 3 * wave function in benzaldehyde also have been exposed by analysis of nuclear hyperfine interactions. 15 Aromatic carbonyl derivatives wherein the lowest triplet state has n* character have been less studied.…”

Electronic Properties of Triplet States of Azabenzenes

“…Here the n n* state is nearly degenerate with the lowest nn* triplet [2] whereas in 7 the first two triplet states are separated by more than 1 eV [11]. Therefore we can assume that in 2 and 4 spinorbit coupling, which was not taken into account in our calculation of ZFS parameters, leads to a reduction of D similar as in case of some enones and benzaldehyde derivatives [12]. Also the vibronic coupling between both states [2] could influence the magnitude of the ZFS parameters of the lowest Unauthenticated Download Date | 5/9/18 6:29 AM Table 1.…”