Tunneling Splittings for "O···O Stretching" and Other Vibrations of Tropolone Isotopomers Observed in the Infrared Spectrum Below 800 cm-1
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- 作者：Richard L. Redington ; Theresa E. Redington ; Robert L. Sams
- 刊名：Journal of Physical Chemistry A
- 出版年：2008
- 出版时间：February 21, 2008
- 年：2008
- 卷：112
- 期：7
- 页码：1480 - 1492
- 全文大小：461K
- 年卷期：v.112,no.7(February 21, 2008)
- ISSN：1520-5215
文摘
Fourier transform infrared absorption spectra containing evidence for about two dozen spectral tunnelingdoublets are reported for gaseous tropolone(OH), tropolone (OD), and 18O,18O-tropolone(OH) in the 800 to300 cm-1 spectral range. No FTIR absorption was detected in the 300-150 cm-1 range. The known zero-point (ZP) tunneling splitting values 
s/gifchars/Delta.gif" BORDER=0 >0 = 0.974 cm-1 for tropolone(OH) (Tanaka et al.) and 0.051 cm-1 fortropolone(OD) (Keske et al.) allow vibrational state-specific tunneling splittings s/gifchars/Delta.gif" BORDER=0 >v to be estimated forfundamentals including three with strong O···O stretching displacements [cf. for tropolone(OH) s/gifchars/nu.gif" BORDER=0 >13(a1) =435.22 cm-1 with Hs/gifchars/Delta.gif" BORDER=0 >13 = 1.71 cm-1 = 1.76 Hs/gifchars/Delta.gif" BORDER=0 >0, and for tropolone(OD) s/gifchars/nu.gif" BORDER=0 >13(a1) = 429.65 cm-1 with Ds/gifchars/Delta.gif" BORDER=0 >13 =0.32 cm-1 = 6.27 Ds/gifchars/Delta.gif" BORDER=0 >0]. The majority of s/gifchars/Delta.gif" BORDER=0 >v splittings in the sub-800 cm-1 range are dilated relative to theisotopomer s/gifchars/Delta.gif" BORDER=0 >0 values. The FTIR spectra demonstrate the presence of dynamic couplings and potential functionanharmonicity in addition to revealing s/gifchars/Delta.gif" BORDER=0 >v splittings and many OH/D and 18O/16O isotope effects. Approximatevalues are obtained for the ZP splittings 88s/gifchars/Delta.gif" BORDER=0 >0 and 86s/gifchars/Delta.gif" BORDER=0 >0 of the doubly and singly 18O-labeled isotopomers oftropolone(OH). The diverse values of the observed s/gifchars/Delta.gif" BORDER=0 >v/s/gifchars/Delta.gif" BORDER=0 >0 splitting ratios underscore the inherentmultidimensionality and corner-cutting activities entering the state-specific tunneling processes of the tropolonetautomerization reaction.