The effect of pressure and temperature on the vibrational spectra of different hydrogen bonded systems

The effect of pressure and temperature on the vibrational spectra of hydrog en bonded systems has been studied on amides, thioamides, carboxylic acids and urea. The compounds under investigation are indicative for the kind of hydrogen bonding changing from pure intermolecular to intramolecular and di meric forms. The discussion of the temperature dependence on the fundamenta ls involved in the hydrogen bonding is straightforward but the pressure dat a are much more complicated and only if the changes in the crystalline stat e at different pressures are known, we will have a better understanding of the dependence of some fundamentals in the hydrogen bonded systems. A clear example of this approach is given for urea. (C) 2001 Elsevier Science B.V. All rights reserved.