Fluorescence lifetime of rovibrational states of h4-acetaldehyde and spectra of d4-acetaldehyde

State-Resolved Dynamics of Dissociation of Triplet Acetaldehyde: Rate of Appearance of Fragment HCO and Decay of Excited States of Parent Molecule

“…In this region, only small portion of spectrum is assigned because of its complicated spectral features. Many groups reported spectra and assignments of à 1 A ‘ ‘ −X̃ 1 A ‘ near the origin of à 1 A ‘ ‘ . ,− However, because the torsional motion of methyl and inversion of aldehyde hydrogen interact, definite assignments of vibrational and rotational levels at a vibrational energy near and above the torsional barrier ∼600 cm -1 remain unresolved. Rovibrational assignments including the interaction of torsional and rotational motions at energy near and above 600 cm -1 are currently under investigation.…”

“…The lifetime of J K a = 0 0 of vibrational ground state of à 1 A ‘ ‘ is reported to be 171 ns resulting mainly from internal conversion to the ground electronic state . The rate of internal conversion is expected to increase with energy.…”

Dynamics of multidissociation paths of acetaldehyde photoexcited at 157 nm: Branching ratios, distributions of kinetic energy, and angular anisotropies of products

“…Walzl et al 4 investigated the electronic states of acetaldehyde using electron-impact spectroscopy; the features located at approximately 4.2 and 6.0 eV in an energy-loss spectrum are assigned to n → ‫ء‬ and → ‫ء‬ transitions, respectively, and the features above 6.5 eV are attributed to various Rydberg transitions. The absorption features are assigned to vibrational progressions of three electronic transitions n → 3s, n → 3p, and n → 3d of acetaldehyde according to the assignment of Walzl et al 4 Much experimental [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] and theoretical work [27][28][29][30][31][32][33][34][35][36][37][38] has been devoted to photolysis of acetaldehyde via S 1 -state excitation. The absorption features are assigned to vibrational progressions of three electronic transitions n → 3s, n → 3p, and n → 3d of acetaldehyde according to the assignment of Walzl et al 4 Much experimental [8][9][10][11][12][13][14][15][16]…”

“…Three primary dissociation channels-to CH 3 + HCO, CH 3 CO+ H, and CH 4 + CO-are observed in the ultraviolet photolysis of acetaldehyde, especially the preferential C-C bond cleavage channel. Chen and co-workers investigated the dissociation dynamics, 18 the fluorescence excitation spectra, 6,19 and the fluorescence lifetime and quantum beats [19][20][21] of acetaldehyde via its S 0 → S 1 transition. 11 S 1 acetaldehyde might convert to the T 1 state via intersystem crossing followed by C-C bond breaking if excitation energy is greater than the dissociation barrier of ϳ31 650 cm −1 above ground-state acetaldehyde.…”