A Hole-Burning Study of the Zero-Field Splitting of the Triplet Ground and Excited States of 2,2-Dinaphthylcarbene in n-Heptane and n-Hexane at 1.7 K

Abstract

Spectral holes were burned within the inhomogeneous 0,0 fluorescence excitation lines of the T0 → T1 transition of 2,2-dinaphthylcarbene (2,2-DNC) in n-heptane at 1.7 K. The spectrum of holes, attributed to the Z/cis conformer of 2,2-DNC, was interpreted with a model taking into account the zero-field splitting (zfs) of both triplet states contributing to the transition, enforced C 2 v symmetry, and the dominance of internal conversion in the relaxation of the excited T1 state. Under enforced high symmetry, the number of possible electronic transitions between different spin sublevels of the ground T0 and excited T1 states is reduced and the analysis of spectral position of holes can only provide the differences between the zfs parameters: D 0 − D 1 = 0.558 ± 0.001 cm-1 and E 0 − E 1 = 0.0183 ± 0.001 cm-1.

Read-out of single spins by optical spectroscopy

“…Hence, it can be anticipated that electronic transitions from every spin sublevel of the ground state to every spin sublevel of the excited state are possible. On the other hand, the symmetry of a defect often give an invariant direction of the principal spin axes [55]. Therefore, taking into account the C 3v symmetry of the N-V defect, the conservation of principal spin axes can be assumed.…”