Molecular Relaxation Processes in Nucleic Acids Components as Probed with Raman Spectroscopy

摘要

In this work the Raman total half bandwidths of five free nucleic acids components (cytidine - 5' - monophosphate, 2' - deoxycytidine 5' - monophosphate, 2' - deoxyguanosine - 5' - monophosphate, thymidine - 5' - monophosphate disodium salt hydrate and uridine - 5' - monophosphate disodium salt) have been measured, respectively. Raman scattering can be used to study the fast molecular relaxation processes of free nucleic acids components in solid phase. The dependencies of the total half bandwidths and of the corresponding global relaxation times, on functional groups and on the type of DNA and RNA constituents, are reported. In our study, the full widths at half -maximum (FWHMs) for the Raman bands of these nucleic adds components, are typically in the wavenumber range from 9 to 28 cm(1). Besides, it can be observed that the (sub)picosecond dynamics studied in this work, has a global relaxation time value smaller than 1.18 ps and larger than 0.38 ps. We have found that the band centered at 1264 cm(1) for cytidine - 5' - monophosphate, the profile near 1373 cm(1) attributed to thymidine - 5' - monophosphate disodium salt hydrate and the band around 1233 cm(1) attributed to uridine - 5' - monophosphate disodium salt, respectively, are suitable for studying the dynamical behavior of molecular fragments in nucleic adds components. For the case of solid phase samples of nucleic acids components, we can suppose that the dominant relaxation mechanism is of the vibrational type one.