Applet Launcher Applet 1 Applet 2 Applet 3 Applet 4 Applet 5 Applet 6   Rotational Raman Spectroscopy Centrifugal Distortion page 2 of 3     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   To the left of the spectra window there is a button labelled Centrifugal Distortion. Clicking on this brings up a window. The value of D is initially zero as in the Rigid Rotor Model. Moving the slider varies the value of D for . Moving the slider to the right sets D as positive. Move the slider slowly increasing D positively. See how this changes the rotational energy levels of . Q3.6 How does this affect the spectra? Why do the Stokes lines move closer together and the Anti-Stokes lines move further apart? In some molecules the centrifugal constant is large enough that spectral lines appear on top of each other. Ultimately a sequence of lines can reach a "band head" and then reverse direction. Applet 2 shows an example of this. Q3.7 Describe what has happened to the energy levels to produce two overlapping spectral lines. Q3.8 What are the J values for the two lines that occur on top of each other?     << previous page www.physchem.ox.ac.uk next page >>