Terahertz Technology Applied In The Molecular Recognition And Reaction Study

The terahertz time-domain spectroscopy(THz-TDS), with the following advantages: coherent, nondestructive, and sensitivity, is currently finding new applications in areas of biomedical, chemical and pharmaceutical. Weak interaction in biology and chemistry systems, such as hydrogen bonding, and van der Waals' force, plays an irreplaceable role in the network structure, interactions, and functionality of biomolecules. THz spectroscopy is particular sensitive to these interactions, and is proven to be an effective analytical approach. The density functional theory(DFT) has been used in the modeling of the THz absorption spectroscopy of molecules to help understand the origin of the characteristic absorption bands. This work presents a detailed study of the weak interaction in biology and chemistry system with THz-TDS. An analysis of the characteristic absorption bands is also presented with the help of DFT calculation, which includes:1. Solid-state interaction study. We studied the interaction ability of urea and four pyrimidine bases without the participation of water with THz-TDS technology. We also monitored the reaction process of uracil-urea and thymine-urea with TDS, and compared the reaction rate. Last, the origin of the THz absorption bands of cocrystal were explained with DFT calculation. This research is very useful in understanding the micromechanism of molecular interaction.2. Dehydration of monohydrate study. We used THz-TDS to study the L-asparagine monohydrate and L-asparagine, and compared their THz absorption spectroscopy. Then the dehydration process of L-asparagine monohydrate was also monitored with TDS. Last the origin of the THz absorption bands of L-asparagine monohydrate was explained with DFT calculation. This result shows that THz technology is promising in drug monitoring.