Time-resolved multiple probe spectroscopy

Abstract

Time-resolved multiple probe spectroscopy combines optical, electronic, and data acquisition capabilities to enable measurement of picosecond to millisecond time-resolved spectra within a single experiment, using a single activation pulse. This technology enables a wide range of dynamic processes to be studied on a single laser and sample system. The technique includes a 1 kHz pump, 10 kHz probe flash photolysis-like mode of acquisition (pump-probe-probe-probe, etc.), increasing the amount of information from each experiment. We demonstrate the capability of the instrument by measuring the photolysis of tungsten hexacarbonyl (W(CO)(6)) monitored by IR absorption spectroscopy, following picosecond vibrational cooling of product formation through to slower bimolecular diffusion reactions on the microsecond time scale.

Femtosecond to microsecond observation of the photochemical reaction of 1,2-di(quinolin-2-yl)disulfide with methyl methacrylate

“…The experimental setups and procedures used for TEAS and TVAS measurements have been described previously, [28][29][30][31][32] therefore only details specific to the present study are provided here.…”

“…The transient absorption spectroscopy experiments were performed using the LIFEtime laser system 28,29 at the Central Laser Facility of the Rutherford Appleton Laboratory (RAL, for temporal windows from 200 fs up to ~50 μs) in continuous measurements, or an ultrafast laser system at the University of Bristol (for temporal windows from 100 fs up to ~1.3 ns). The experimental setups and procedures used for TEAS and TVAS measurements have been described previously, [28][29][30][31][32] therefore only details specific to the present study are provided here.…”

“…9 For TVAS measurements on nanosecond to microsecond time intervals, sample flow out of the probe laser volume perturbed the measured kinetics. 28 Therefore, TVA spectra at each time delay were corrected for flow effects using TVA spectra of tungsten hexacarbonyl (W(CO)6) in cyclohexane solution obtained at the same flow rate as the TVAS measurements of QSSQ. 28 The W(CO)6 data are presented in Figure S1 of Supplementary Information.…”

“…28 Therefore, TVA spectra at each time delay were corrected for flow effects using TVA spectra of tungsten hexacarbonyl (W(CO)6) in cyclohexane solution obtained at the same flow rate as the TVAS measurements of QSSQ. 28 The W(CO)6 data are presented in Figure S1 of Supplementary Information. All measurements were performed without purging molecular oxygen from the sample solutions, unless otherwise specified.…”

“…We estimate the concentration of the QS-MMA radical in the probed sample volume to be 0.30 mM under our experimental conditions, using a pump energy of 200 nJ/pulse, pump beam diameter of 100 μm, 28,31 sample pathlength of 100 μm, optical density of QSSQ of 0.5 OD, and a quantum yield for the survival of the two QS radicals of 31% (Table S1). The concentration of molecular oxygen in aerated CDCl3 solution is 2.4 mM assuming the solubility of molecular oxygen in CDCl3 is the same as CHCl3.…”