ABSTRACT
Infrared spectroscopy detects transitions between the vibrational energy levels of a molecule. The chapter outlines some aspects of practical spectroscopy that apply to the problems that are of concern in the study of hydrogen bonding. The intensity of the free carbonyl band increases with the concentration of ether functional groups in the mixture, as urethane N-H to ether oxygen hydrogen bonds are formed at the expense of self-association interactions. The chapter discusses one basic and inherent condition for infrared absorption, namely that the frequency of the absorbed radiation must correspond to the frequency of a normal mode of vibration and hence a transition between vibrational energy levels. The quantitative analysis of polymers in transmission studies is based on the Beer-Lambert law. The change in energy of these nuclear vibrations upon interaction with radiation of suitable frequency is the origin of the vibrational spectrum.
