High resolution electronic spectroscopy of molecular conformers. Methyl- and ethyl-3-aminobenzoic acid esters

Conformational analysis by laser spectroscopy in the gas phase: p-methoxyphenethylamine (a neurotransmitter)

“…Independent CIS calculations 13 show that there are no large '' electronic '' contributions to the TM orientations in these off-axis structures, probably owing to the presence of the methoxy group, which appears to '' lock '' the electronic structure of the benzene ring into place. 17 Thus, the observed TM orientations in the high resolution spectra of MPEA also may be used to unambiguously assign specific bands to specific conformers of the isolated molecule.…”

Applications of ultrafast spectroscopy to sunscreen development, from first principles to complex mixtures

“…In the case of meta and para-MA, herein referred to as m-and p-MA (structures shown in Figure 3(a) For m-MA, two λ pu were studied: 325 nm (the S 1 origin [187]) and 300 nm (higher energy S 1 excitation). For p-MA, the S 1 and S 2 states were in close proximity [186], and the calculated oscillator strength for the S 1 ← S 0 transition was much lower than S 2 ← S 0 transition.…”

Conformationally Induced Changes in the Electronic Structures of Some Flexible Benzenes. A Molecular Orbital Model

“…This is because such spectra are sensitive to the shape of the molecule and possible changes in this shape produced by the absorption of light. Recently, we have applied this technique to a series of compounds containing benzene as a chromophore, including n -propylbenzene and other alkylbenzenes, 2-phenethyl alcohol, 2-phenethylamine, 3-phenylpropionic acid, several benzoic acid esters, and their water clusters. − Surprisingly, we found that the orientations of the S 1 −S 0 electronic transition moment (TM) in the molecular frames of different conformers of the same molecule quite often are different, a phenomenon that had not been observed before…”