# DOES A HEAVY CENTRAL ATOM REDUCE THE RATE OF VIBRATIONAL ENERGY RELAXATION?

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 Title: DOES A HEAVY CENTRAL ATOM REDUCE THE RATE OF VIBRATIONAL ENERGY RELAXATION? Creators: Kerstel, E. R. Th.; Lehmann, K. K.; Mentel, T. F.; Pate, Brooks H.; Scoles, G. Issue Date: 1991 Abstract: We have used high resolution infrared spectrocopy to study the IVR process in the series of molecules $(CH_{3})_{3}X-C\equiv C-H (X = C,Si$, and $Sn)$. Our optothermal spectrometer is interfaced with two color center lasers that allow us to obtain both the fundamental and first overtone spectra of the acetylenic C-H stretch. All six spectra show homogeneously broadened lines. The width of the Lorentzian lineshapes corresponds to the lifetime of the initial vibrational excitation of the C-H stretch. In the fundamental we find that the linewidth decreases as the mass of the central atom increases suggesting that a heavy atom does inhibit IVR. The homogeneous lifetime is about 200 ps in the carbon species and increases to about 6 ns in the tin compound. However, a simple mass effect cannot fully explain the measured linewidths in both the fundamental and overtone. Other possible explanations of the data will be presented."" URI: http://hdl.handle.net/1811/12437 Other Identifiers: 1991-RC-4