Direct Timing of the Relaxation from Selected Excited States; Beta-Naphthylamine

The fluorescence of β-naphthylamine vapor in the low-pressure region was timed directly using a high-speed laboratory light modulator. Emission was from defined, and variable quantum states initially pumped with high-intensity monochromatic light. The energy of irradiation was swept over a range of 10 000 cm−1, encompassing two excited electronic manifolds. The results then constitute a direct timed measurement of the relaxation from individual vibronic states as the energy of excitation is continuously increased. This is then a spectrum of vibronic lifetimes which is discussed in terms of various theories for electronic relaxation.