The optical properties of Li- and Na-DNA films

✍ Scribed by T. Weidlich; S. M. Lindsay; A. Rupprecht

• Book ID: 102761198
• Publisher: Wiley (John Wiley & Sons)
• Year: 1987
• Tongue: English
• Weight: 850 KB
• Volume: 26
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360260310

✦ Synopsis

We have measured the refractive indices of highly crystalline Liand Na-DNA wet-spun f i l m s as a function of their water content Using an immersion technique. We calculated the molecular polarizabilities of a DNA base pair using the Lorentz-Lorenz relation for anisotropic materials, the measured water contents, and densities corrected for void formation. For Li-DNA, the polarizabilities are independent of the relative humidity, whereas for Na-DNA, there are large changes at the A-B transition and aLso at low humidities. The average polarizability of A-Na-DNA is in agreement with that calculated from refractive index increments and also as calculated by a simple addition of bond polarizabilities, whereas the values for Liand B-Na-DNA are about 30% larger than the calculated values. We propose that these anomalous values are due to nonlinear polarizabilities of the phosphate group.