The conformers of (a) (2-chloroethyl)-benzene (CEB) and (b) (2-fluoroethyl)-benzene (FEB), with the predicted transition dipole moment (TDM) alignments for the transition. “A” and “G” indicate the anti and gauche conformers. Relative energies are computed at the level.
(a) Two-color R2PI spectra of FEB. The origin band for the anti conformer “A,” at , lies to the blue of the gauche conformer origin “G” at . Traces (b) and (c) show the UV-UV hole burning spectra for the FEB anti and gauche conformers, respectively, obtained by probing origin bands A and G on trace (a).
The two-colour R2PI spectra of selected mass channels, recording (a) CEB and (b) the CEB isotopomer containing chlorine 37. The origin bands for the anti and gauche conformers “A” and “G” overlap at . The expanded section of traces (a) and (b) shows the transition with the most pronounced shift between the two CEB isotopmers . Traces (c) and (d) show the UV-UV hole burning spectra for the CEB anti and gauche conformers, respectively, taken by probing either band “” (anti) or “” (gauche). See Figs. 5 and 6 for band “.”
The FEB R2PI experimental contours at origin bands “A” at and “G,” at (see Fig. 2). Predicted band contours are also presented for the anti (conf. A) and gauche (conf. G) conformers. Simulation parameters are taken from Table II and include and .
The CEB R2PI experimental band contours measured at bands “,” and “” (see Fig. 3). Simulated contours for the anti (conf. A) and gauche (conf. G) conformers are also shown, simulation parameters taken from Table II and including and .
(a) The R2PI CEB rotational band contour of the origin transition, measured at . This contour was reproduced in (b) by adding the experimental band contours taken at band “,” , and band “,” (see Fig. 3), in a ratio of 0.75:1.0 gauche:anti, and by shifting the anti conformer to the red by . Experimental contours were first normalized against predicted anti and gauche contours.
The R2PI spectra taken at selected mass channels for (a) the FEB monomer and (b) the singly hydrated water cluster. Trace (c) shows the UV-UV hole burning spectrum of the FEB anti conformer, blueshifted by for comparison (see Fig. 2).
The R2PI spectra taken at selected mass channels for (a) the CEB monomer, (b) the singly hydrated water cluster and (c) the water cluster containing the isotope. The feature marked “” shows an redshift relative to the spectrum in trace (b). Trace (d) shows the UV-UV hole burning spectrum of the CEB anti conformer (Fig. 3), redshifted by for comparison.
Trends in anti/gauche conformational stability for molecules of class .
Ab initio calculated molecular properties of CEB and FEB.
Vibrational assignments for the R2PI spectrum of FEB.
Vibrational assignments for the R2PI spectrum of CEB.
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