Ultraviolet Absorption Spectra of Polyribonucleotides

Abstract

The optical absorption spectra of single stranded poly A, poly U, poly G, poly C and double stranded poly A, poly C, poly (A+U), copoly (A−U), poly (G+C), copoly (G−C), RDV–RNA and CPV–RNA in the aqueous solution were measured in the wavelength range from 3100Å to 2000Å in order to study the electronic structures by comparing these experimental data with those calculated theoretically within the frame-work of Frenkel exciton model by T. Miyata and S. Yomosa.
When the “solvent effect” is taken into account, it is possible to identify that the first π–π^* transition by theoretical calculation lies near 2800 Å for poly (A+U) and poly (A−U).
The sum of the oscillator strength obtained from the measurement was plotted in order to compare with the value calculated theoretically and also to see the possibility to apply the sum rule for the analysis of the electronic structure of polynucleotides. This analysis suggests that the polynucleotides have a very strong absorption band in the higher energy range than 10 eV.