V. Grassian, J. Warren, E. Bernstein
Apr 15, 1989
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Influential Citations
53
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Journal
Journal of Chemical Physics
Abstract
One‐color time‐of‐flight mass spectra (mass resolved excitation spectra) for jet‐cooled 4‐dimethylaminobenzonitrile (4‐DMABN) and some of its chemical analogs, dimethylaniline (DMA), 3‐dimethylaminobenzonitrile (3‐DMABN), N, N‐dimethyl‐4‐(trifluoromethyl)aniline (4‐CF3‐DMA), and 4‐(d6‐dimethylamino)benzonitrile (4‐d6‐DMABN), are presented and analyzed. Near the origin of the S1←S0 transition the low frequency modes can be assigned to motions of the dimethylamino group for this series of molecules. The inversion motion of the dimethylamino group and the dimethylamino group torsion about the Cipso–N bond (the twist coordinate) in S1 give rise to the most prominent peaks in this spectrum. The potential parameters for the twist coordinate of 4‐DMABN and DMA are quite similar in S1: B=0.546, V2=175, and V4=525 cm−1 for 4‐DMABN and B=0.546, V2=175, and V4=515 cm−1 for DMA. The V2 and V4 terms are slightly larger for 3‐DMABN and 4‐CF3‐DMA. The inversion motion is also similar for these molecules but is more anha...