Abstract-Terahertz spectra of DNA nucleobase crystals: A joint experimental and computational study

• Wang Fang^a, d, 
• Zhao Dongbo^b, 
• Dong Hao^c, 
• Jiang Ling^a, 
• Liu Yunfei^a,, 
• Li Shuhua^b, 

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• ^a College of Information Science and Technology, Nanjing Forestry University, Nanjing 210037, China
• ^b School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
• ^c Kuang Yaming Honors School, Nanjing University, 210023, China
• ^d School of Electronic and Information Engineering, Sanjiang University, Nanjing 210012, China
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• https://www.blogger.com/blogger.g?blogID=124073320791841682#editor/target=post;postID=3006732806227992635
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• Terahertz (THz) spectra of DNA nucleobase crystals were experimentally studied by terahertz time domain spectroscopy (THz-TDS), Fourier transform infrared spectroscopy (FTIR), and computationally studied by the generalized energy-based fragmentation approach under periodic boundary conditions (denoted as PBC-GEBF). We analyzed the vibrational spectra of solid-state DNA nucleobases and assigned the corresponding vibrational modes to the main peaks in the experimental spectra with the PBC-GEBF results. The computational results were verified to be in good accordance with the experimental data. Harmonic vibrational frequency results revealed that all the vibrational modes belong to collective vibrational modes, which involve complicated mixtures of inter- and intramolecular displacements, somewhere in the vicinity of 0.5–9 THz