Search results for "CH3"
showing 3 items of 13 documents
Calculated Line Broadening Coefficients in the nu2 Band of CH3D Perturbed by Helium
2003
International audience; Line broadening coefficients have been calculated, at room temperature, for lines in the P and R branches of the nu2 band of monodeuterated methane. A properly symmetrized semiclassical model with parabolic relative trajectories has been used. Two interaction potential models have been considered. The first is a Lennard-Jones type atom-atom potential, while the second one was derived from ab initio calculations. The calculated line widths were compared to the available experimental data and a satisfactory agreement was found, although the model contains no other adjustable parameters than the four atomic Lennard-Jones ones. Nonetheless, failures of calculations have …
Preliminary analysis of CH3D from 3250 to 3700 cm(-1)
2006
International audience; The infrared spectrum of CH3D from 3250 to 3700 cm(-1) was studied for the first time to assign transitions involving the nu(2) + nu(3), nu(2) + nu(5), nu(2) + nu(6), nu(3) + 2(nu 6) and 3 nu(6) vibrational states. Line positions and intensities were measured at 0.011 cm(-1) resolution using Fourier transform spectra recorded at Kitt Peak with isotopically enriched samples. Some 2852 line positions (involving over 900 upper state levels) and 874 line intensities were reproduced with RMS values of 0.0009 cm(-1) and 4.6%, respectively. The strongest bands were found to be nu(2) + nu(3) at 3499.7 cm(-1) and nu(2) + nu(6) at 3342.5 cm(-1) with integrated strengths, respe…
Methyl Radical in Clathrate Silica Voids. The Peculiar Physisorption Features of the Guest-Host Molecular Dynamics Interaction.
2016
EPR line shape simulations of CH3/SiO2 clathrates and comparison to CH3/N2O and CH3/SiO2 experiments reveal the motional conditions of the CH3 radical up to the unusual regime of its stability, the high-temperature diffusional regime, at 300 K. In the low-temperature region, the CH3 in clathrates is found to rotate around the in-plane axes even at as low temperatures as 3.8 K. However, nonrotating methyls performing only libration about the C2-axes as well as around the C3-axis are also found, proving the existence of special sites in the clathrate voids that begin to accumulate a significant fraction of methyl radicals at temperatures below approximately 7 K. A distinctive feature in the s…