This Letter presents an experimental and theoretical study of femtosecond time-resolved vector correlations in methyl iodide (CHI) electronic predissociation via the second absorption B-band at 201.2 nm. The time evolution of the phenomenological anisotropy parameters β was determined from time-resolved photofragment angular distributions obtained by means of the femtosecond laser pump-probe technique coupled with velocity map imaging detection of vibrational ground-state CH(ν = 0) fragments and spin-orbit excited I*(P) atoms.
View Article and Find Full Text PDFWe present a detailed study of two-color two-photon excited fluorescence in indole dissolved in propylene glycol. Femtosecond excitation pulses at effective wavelengths from 268 to 293.33 nm were used to populate the two lowest indole excited states (1)La and (1)Lb and polarized fluorescence was then detected.
View Article and Find Full Text PDFWe present the experimental and theoretical study of the two-photon excited polarized fluorescence of p-terphenyl dissolved in cyclohexane/paraffin. The fluorescence was produced within a two-color two-photon (2C2P) excitation scheme utilizing simultaneous absorption of two femtosecond laser pulses at 400 nm and at 800 nm with the total excitation energy of 4.649 eV.
View Article and Find Full Text PDFWe present the full quantum mechanical expressions for the polarization differential cross sections of the photofragments produced in slow predissociation of a parent molecule via isolated rotational branches. Both radial and Coriolis nonadiabatic interactions between the molecular potential energy surfaces have been taken into account. The expressions describe the recoil angle distribution of the photofragments and the distributions of the photofragment angular momentum polarization (orientation and alignment) in terms of the anisotropy parameters of the ranks K=0,1,2.
View Article and Find Full Text PDFWe present a theoretical framework for calculating the recoil-angle dependence of the photofragment angular momentum polarization taking into account both radial and Coriolis nonadiabatic interactions in the diatomic/linear photodissociating molecules. The parity-adapted representation of the total molecular wave function has been used throughout the paper. The obtained full quantum-mechanical expressions for the photofragment state multipoles have been simplified by using the semiclassical approximation in the high-J limit and then analyzed for the cases of direct photodissociation and slow predissociation in terms of the anisotropy parameters.
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