Near IR overtone spectral investigations of cyclohexanol using local mode model--evidence for variation of anharmonicity with concentration due to hydrogen bonding.
The near infrared vibrational overtone absorption spectrum of liquid phase cyclohexanol in carbon tetrachloride in different concentrations are examined in the region Deltav=2, 3 and 4. The free and bonded OH local mode mechanical frequency values and anharmonicity values obtained from fitting the overtones are analysed. The observation supports the conclusions drawn from earlier experimental studies on anharmonicity variation of OH-stretching vibrations of alcohols due to intermolecular hydrogen bonding. Our observation is also in agreement with the ab initio calculations on water dimer and trimer. Mechanical anharmonicity of bonded OH-stretching bands tends to increase as a consequence of strong hydrogen bonding at higher concentrations.
John
Usha
U
Laser and Spectroscopy Laboratory, Department of Physics, Faculty of Science, Cochin University of Science and Technology, Cochin 682022, Kerala, India. jousha@eth.net
Nair
K P R
KP
D002244:Carbon / Q000737:chemistry; D002251:Carbon Tetrachloride; D003511:Cyclohexanols / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D006860:Hydrogen Bonding; D006878:Hydroxides / Q000737:chemistry; D008956:Models, Chemical; D015394:Molecular Structure; D013055:Spectrophotometry, Infrared; D014732:Vibration; D014867:Water / Q000737:chemistry
D003511:Cyclohexanols; D006878:Hydroxides; D014867:Water; D002244:Carbon; D006859:Hydrogen; C031356:hydroxide ion; D002251:Carbon Tetrachloride