The negative ion photoelectron spectrum of 7Li~-is reported at 488 nm (2.540 eV). Three electronic bands are observed in this spectrum and are assigned to the following photodetachment transitions: 7Li2, 14+ --~_.7 '--2 + 7'

The Raman noncoincidence effect has been used to investigate the changes in intermolecular interactions induced by applying high pressure to neat liquid alkyl benzoates. The noncoincidence of the carbonyl band of a homologous series of straight chain alkyl benzoates (methyl, ethyl, propyl, butyl, and hexyl benzoate) and a branched chain alkyl benzoate (2-ethylhexyl benzoate) was measured at 20 and 40 °C over the pressure range 1−5000 bar. The density was measured as a function of pressure for all molecules. A transition point dividing the noncoincidence behavior as a function of density into two regions was found, for all molecules except methyl benzoate. Below the transition point, at lower density, the noncoincidence value was relatively insensitive to changes in density, while above the transition point, the noncoincidence value dropped sharply with increasing density. The decrease in the value of noncoincidence above the transition point was interpreted as the change in intermolecular interactions resulting from the conformational change in favor of a “folded” form of the alkyl side chain shielding the carbonyl group. To examine the plausibility of the presence of energetically allowable conformations with a folded alkyl side chain, conformational searches based on molecular mechanics calculations have also been performed. The strain energy of some alkyl benzoate conformers with folded side chain was calculated to be within a few kcal/mol of the global minimum conformation. Both the experimental results and the conformational analysis suggest that the population of the folded conformer increases under high-pressure conditions owing to its compactness.

We present the photoelectron spectrum of CsO−, recorded using 2.540 eV photons. This spectrum provides a direct measurement of the X 2Σ+–A 2Π energy splitting in CsO, which is found to be 0.135±0.025 eV. This work also establishes that the ground state of CsO− is 1Σ+. In addition, the adiabatic electron affinity of CsO is found to be 0.273±0.012 eV, while the D0 value for the X 1Σ+ state of CsO− (with respect to Cs+O−) is found to be 1.84±0.15 eV. Molecular parameter estimates for CsO− are also extracted from the spectrum.

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