Investigation of terahertz spectra of chlorophyll
Author(s): JIANG Ling, YU Jiangping, XU Yutian, LI Chun, SUN Haijun, XU Li, LIU Yunfei
Pages: 181-184
Year: 2015 Issue: 6
Journal: Journal of Nanjing Forestry University(Natural Science Edition)
Keyword: terahertz spectra; pine chlorophyll; FTIR; DFT;
Abstract: This paper presents the investigation of the THz spectra of chlorophyll of masson pine leaf, chlorophyll a and b standard sample by using Fourier transform infrared spectroscopy ( FTIR) and density functional theory ( DFT) , in or?der to study the vibration and rotation of chemical bonds in chlorophyll molecule at THz frequencies, which will be used to identify the components in mixing biological samples. The frequency shift characteristic of THz spectra of chlorophyll due to the change of molecular structure will efficiently detect the development of pine wilt disease. The THz spectra of the extracted chlorophyll of masson pine leaf display a strong absorption at 2.86 THz, and weak absorption at the same frequency occurs for chlorophyll a standard sample, and chlorophyll b standard sample, which originates from porphyrin ring and phytol in the chlorophyll structure. In the other frequencies, the absorptions were not distinct. Based on the ab?sorption performance of chlorophyll, we can identify the mixing biological samples. We studied the theoretical mechanism of absorption frequencies for chlorophyll by terms of DFT. The calculated results indicate the vibration and rotation origi?nated from intermolecular interactions have more important effect on the THz absorption spectra compared with intramo?lecular interactions.
Pages: 181-184
Year: 2015 Issue: 6
Journal: Journal of Nanjing Forestry University(Natural Science Edition)
Keyword: terahertz spectra; pine chlorophyll; FTIR; DFT;
Abstract: This paper presents the investigation of the THz spectra of chlorophyll of masson pine leaf, chlorophyll a and b standard sample by using Fourier transform infrared spectroscopy ( FTIR) and density functional theory ( DFT) , in or?der to study the vibration and rotation of chemical bonds in chlorophyll molecule at THz frequencies, which will be used to identify the components in mixing biological samples. The frequency shift characteristic of THz spectra of chlorophyll due to the change of molecular structure will efficiently detect the development of pine wilt disease. The THz spectra of the extracted chlorophyll of masson pine leaf display a strong absorption at 2.86 THz, and weak absorption at the same frequency occurs for chlorophyll a standard sample, and chlorophyll b standard sample, which originates from porphyrin ring and phytol in the chlorophyll structure. In the other frequencies, the absorptions were not distinct. Based on the ab?sorption performance of chlorophyll, we can identify the mixing biological samples. We studied the theoretical mechanism of absorption frequencies for chlorophyll by terms of DFT. The calculated results indicate the vibration and rotation origi?nated from intermolecular interactions have more important effect on the THz absorption spectra compared with intramo?lecular interactions.
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