Dependence of Adenine Raman Spectrum on Excitation Laser Wavelength: Comparison between Experiment and Theoretical Simulations.
We acquired the Raman spectra of adenine in powder and aqueous phase using excitation lasers with 532, 633, and 785 nm wavelengths for the region between 300 and 1500 cm-1. In comparison to the most distinct peak at 722 cm-1, the peaks between 1200 and 1500 cm-1exhibited a characteristic increase in cross-section with decreasing excitation wavelength in both phases. This trend can be reproduced by different density functional theory (DFT) calculations for the adenine molecule in the gas phase as well as in the aqueous phase. Furthermore, from the calculation on the π-stacked dimer, hydrogen-bonded dimer, and trimer, we find that this trend toward excitation laser wavelength is not sensitive to the packing. When comparing the Raman spectra given by different excitation wavelength, one should take care in analyzing the cross-section, and present day DFT calculations are able to capture general trends in the excitation laser wavelength dependence of the Raman activity.
Institute of Atomic and Molecular Sciences, Academia Sinica , PO Box 23-166, 10617 Taipei, Taiwan.|Department of Chemistry, National Taiwan University , 10617 Taipei, Taiwan.|Nano Science and Technology Program, Taiwan International Graduate Program, Academia Sinica and National Taiwan University , 10617 Taipei, Taiwan.
Navchtsetseg
N
Nergui
Department of Materials Science and Engineering, National Taiwan University , 10617 Taipei, Taiwan.
Miin-Jang
MJ
Chen
Institute of Atomic and Molecular Sciences, Academia Sinica , PO Box 23-166, 10617 Taipei, Taiwan.|Center for Condensed Matter Sciences, National Taiwan University , 10617 Taipei, Taiwan.
Juen-Kai
JK
Wang
Institute of Atomic and Molecular Sciences, Academia Sinica , PO Box 23-166, 10617 Taipei, Taiwan.|Department of Physics, National Taiwan University , 10617 Taipei, Taiwan.
Yuh-Lin
YL
Wang
Institute of Atomic and Molecular Sciences, Academia Sinica , PO Box 23-166, 10617 Taipei, Taiwan.
Cheng-Rong
CR
Hsing
Institute of Atomic and Molecular Sciences, Academia Sinica , PO Box 23-166, 10617 Taipei, Taiwan.
Ching-Ming
CM
Wei
Institute of Atomic and Molecular Sciences, Academia Sinica , PO Box 23-166, 10617 Taipei, Taiwan.
Kaito
K
Takahashi