Ultrafast Transient Absorption of Adamantyl-Phenol

Ultrafast dynamics of adamantyl-phenol was studied by measuring time-resolved absorption changes using transient absorption spectroscopy technique. Adamantyl-phenol molecules dissolved in acetonitrile-water mixture (1:1) were excited by femtosecond laser pulses with the wavelength of 267nm (pump pulse) while their absorption as a function of time was tested with the probe pulses. Probe pulse spectrum was supercontinuum generated in calcium-fluoride (CaF2) crystal pumped by 800nm. Resulting signal was positive, meaning the molecules have negligible fluorescence. After the excitation to first excited electronic state photochemical reaction of photodehydratation takes place and the formation of quinone methide (QM) begins via conical intersection. Quantum-chemical TD-DFT calculations indicate immediate ground state QM formation and the simulated ground state QM spectra is compared to measured one. Obtained results proved the functionality of the used experimental setup which will be used for future research and ultrafast transient absorption measurements of many different samples.