Dephasing Dynamics across Different Local Vibrational Modes and Crystalline Environments

The perturbed free induction decay (PFID) observed in ultrafast infrared spectroscopy was used to unveil the rates at which different vibrational modes of the same atomic-scale defect can interact with their environment. The N3VH0 defect in diamond provided a model system, allowing a comparison of stretch and bend vibrational modes within different crystal lattice environments. The observed bend mode (first overtone) exhibited dephasing times T-2 = 2.8(1)ps, while the fundamental stretch mode had surprisingly faster dynamics T-2 < 1.7 ps driven by its more direct perturbation of the crystal lattice, with increased phonon coupling. Further, at high defect concentrations the stretch mode's dephasing rate was enhanced. The ability to reliably measure T-2 via PFID provides vital insights into how vibrational systems interact with their local environment.

Automated summary

The perturbed free induction decay (PFID) method in ultrafast infrared spectroscopy was used to investigate the interaction rates of different vibrational modes with their environment in atomic-scale defects. The study focused on the N3VH0 defect in diamond and compared the dynamics of stretch and bend modes in different crystal lattice environments. The results showed that the bend mode exhibited slower dynamics, while the stretch mode had faster dynamics driven by its direct perturbation of the crystal lattice.