Dephasing of the ν₁ vibration of isotopic molecules of carbon tetrachloride

Abstract

The isotopic structure of the n 1 line in the isotropic Raman spectrum of liquid carbon tetrachloride was studied. A new fitting procedure was employed enabling one to fit overlapping lines, obtaining dynamic parameters at the same time. The time-correlation functions of vibrational dephasing were first found for each isotopic species present in the liquid at their natural abundance. The isotopic dependence of the characteristic times of vibrational dephasing and vibrational frequency modulation was analysed. The isotopic dependence of dephasing times is contained primarily in the frequency factor: the dephasing times decrease with decreasing line frequency. This dependence entirely outweighs the opposite relationship between the dephasing times and masses. The frequency modulation times show the same trend, which contradicts the simple collision model.

The ν3 − ν4difference band contribution to the CCl4symmetric stretch (ν1) mode

“…Accordingly, the theoretical intensities of the fine structure peaks relative to C 35 Cl 3 37 Cl 1 are as follows: 0.7818, 1, 0.4797, 0.1023, and 0.0082 for C 35 Cl 4 , C 35 Cl 3 37 Cl 1 , C 35 Cl 2 37 Cl 2 , C 35 Cl 1 37 Cl 3 , and C 37 Cl 4 , respectively. The C 35 Cl 3 37 Cl 1 peak location, 459.39 cm −1 , and peak spacing values (listed in Supporting Information with all optimized fitting parameters) agree with empirical and calculated literature values, including the references in Table …”

“…A wealth of knowledge and physical insight has been gained over nearly a century of fundamental study on the structure and properties of carbon tetrachloride, CCl 4 , in the crystalline, liquid, and vapor states. A profound—yet simple—molecule, CCl 4 , has more recently proven useful in ultrafast spectroscopy for investigating liquid dynamics, polarization‐selective vibrational dynamics, solvent effects, and intermolecular bonding at the solute–solvent interface . Significant abundance of naturally occurring CCl 4 isotopomers with well‐known spectroscopic signatures (e.g.…”

Novel Approaches in Spectroscopy of Interparticle Inter-Actions. Vibrational Line Profiles and Anomalous Non-Coincidence Effects

“…:.2 or Tv/T?:.2. The more stable the complex particle, the greater the T,}T or Tv/T ratio, and for the "infinitely'' long-lived particle (CC14 [47]) it reaches the value of about 70. Therefore the ratios between the modulation and dephasing times and the period of vibra- [38,39].…”

“…In Ref. [47], the time-correlation functions of vibrational dephasing have been obtained for each isotopic species present in liquid carbon tetrachloride in their natural abundance, and vibrational dephasing and vibrational frequency modulation of the v1 mode of isotopic molecules have been analyzed in greater detail.…”

Spectroscopy of interparticle interactions in ionic and molecular liquids: Novel approaches

“…[2] has been carefully tested with single vibrational lines in liquids [12], glasses [13], polymers [14], and ionic melts [15]. As far as overlap lines are concerned, it has been successfully employed in order to obtain vibrational relaxation parameters of isotopic species in liquid carbon tetrachloride from the isotopic structure of the ν 1 line in the isotropic Raman spectrum [16] (see Fig. 1), to characterize instantaneous collision complexes in molten alkali halides [17], and to search for indicators of short-time interactions related to cooperativity in glass-forming liquids [18].…”