Applet Launcher Applet 1 Applet 2 Applet 3 Applet 4 Applet 5 Applet 6   Rotational Raman Spectroscopy Intensities of Spectral Lines page 1 of 2     Practical Navigator Introduction The Raman Effect Experimental Techniques 1. Rotational Raman Spectroscopy Interpreting the Spectrum Effect of Bond Length Centrifugal Distortion Intensities of Spectral Lines Nuclear Spin Statistics 2. Real Diatomic Molecules Temperature Spectrum of Nitrogen Isotopic Substitution Nuclear Spin Statistics Predict the Spectrum of Oxygen   Spectra lines have a position and a height. The position of lines has been described as the separation of energy levels. The next section will attempt to give meaning to the intensity of spectral lines. Go back to Applet 1. The intensity of spectral lines is determined by the relative probabilities transitions between various energy levels. Selection rules for rotational Raman allow only J=±2. Q4.1 The intrinsic probability for a transition of a single molecule from J = 0 to J = 2 is the same as that for a transition from J = 1 to J = 3. Why are not all spectral lines equally intense? Q4.2 What is the relationship between the intensities of the Stokes and Anti-Stokes lines? Explain this in terms of the population of the energy levels. The reason that the intensity of the spectral lines tail to zero is the influence on populations of an exponential term:     << previous page www.physchem.ox.ac.uk next page >>