Acrolein: Spectroscopy, Photoisomerization, and Theoretical Considerations

Abstract

The quantum yields of fluorescence (<t>F~0.OO7) and phosphorescence (<t>p~O.OOO04) indicate that excitation results in nearly complete internal conversion and/or photochemistry. Theoretical calculations have been made including the potential energy curves resulting from twisting around the central carboncarbon single bond as well as the terminal carbon-carbon double bond. It appears that photoisomerization cannot occur around the single bond in either the 7r, 7r* or n, ,..* states but could occur around the double bond in the lowest ,.., 7r* triplet state. In the latter case, a potential energy minimum exists near 90° and degeneracy occurs with the ground state. Based on the spectroscopic and theoretical considerations herein reported, an analysis is made of the published spectroscopic results of conjugated keto steroids.

Vibronic spectroscopy and lifetime of S1 acrolein

“…The dynamics of S 1 acrolein relaxation has been actively studied, originally by Becker et al 11 and more recently by Shinohara and Nishi 8 and by Reguero et al 12 Of particular interest are the possibility of photoisomerization and the role of the triplet potential energy surfaces. In the present work, the linewidth of the S 1 vibronic origin has been measured, yielding a lifetime determination for S 1 acrolein that can be compared to theoretical predictions.…”

Electronic excitation energies in solution at equation of motion CCSD level within a state specific polarizable continuum model approach

“…[14][15][16][17][18][19][20][21][22][23] The coupling is realized through a simple strategy which exploits an external macroiteration PCM procedure, 24,25 which requires the calculation of the excited state charge density. This macroiteration procedure is, in general, not the most efficient strategy to introduce the solvent effect because it requires that the calculation on the solute system is performed many times until selfconsistency between the solute charge density and the solvent response is achieved.…”

Excited states of acrolein: abinitio model studies on α,β-unsaturated carbonyl compounds

“…Becker et al (6) suggested that in the lowest nn * triplet state twisting about the carbon-carbon double bond may occur, leading to intersystem crossover to the ground state. Their semiempirical PPP-CI calculations indicated that 3nn* is most stable at a 90" twist angle.…”