Theoretical Study On Surface-enhanced Raman Spectroscopy And Surface-enhanced Hyper-raman Spectroscopy Of Adenine

Raman spectroscopy is a method to study the structure of molecules and molecularspectroscopy. Hyper-Raman scattering(HRS) has aroused much concern because of itsspecial selection rules: all infrared activity is hyper-Raman activity and especially HRS canprobe vibrations that are forbidden in the Raman scattering and Infrared absorption.Nevertheless hyper-Raman scattering(HRS) signal is extremely weak, which is about10-6times the normal Raman scattering cross-section，it is considerably difficult to observe weakHRS modes in experiments.In this thesis, the Gaussian03DFT method was employed to obtain the dipole moment,polarizability adenine molecules, as well as derivative hyperpolarizability dipole moment,polarizability. It is the perfect combination of surface-enhanced Raman scattering(SERS)and hyper-Raman scattering(HRS). Thus the study SEHRS can find more information ofmolecular spectroscopy. Adenine is one of the most important ingredients in the nucleic acidbases, therefore adenine molecules vibration information of the research has importantsignificance. This paper reports the theoretical calculation results of SERS and SEHRS ofadenine, and compared with the experimental results. Bands such as the847cm-1,900cm-1,1079cm-1,1143cm-1and1432cm-1band in the Raman spectrum of super strength havesignificantly enhanced. In the surface-enhanced hyper-Raman scattering, we observed thatthe intensity of1501cm-1band compared to surface-enhanced Raman have significantenhancements, and its attribution analysis.