Dispersion-corrected DFT study on the structural transformations and absorption properties of crystalline 3′-Amino-3′-deoxyadenosine

In this work, the structural, electronic and absorption properties of crystalline 3′-Amino-3′-deoxyadenosine (3′-AD) under hydrostatic compression of 0-300 GPa have been studied by using density functional theory with dispersion correction. The crystal structure of 3′-AD was relaxed using three types of exchange correlation energy and two types of van der Waals corrections at ambient conditions. The results indicate that PBE-TS is the best functional for studying 3′-AD. In addition, the c-direction is much stiffer than the a- and b-axis at 0-150 GPa, suggesting the 3′-AD crystal is anisotropic in the certain pressure region. Besides, pressured-induced formations of covalent bonds in P1 and P1z molecules results the formation of new four-atom ring at 110 GPa, and new five-atom ring at 290 GPa, resceptively. Then, the analysis of the band gap and DOS (PDOS) of 3′-AD indicate that its electronic character changes from insulator at 90 GPa into semiconductor, but the electron transition is much different at 110 GPa. Moreover, the relatively high optical activity with the pressure increases of 3′-AD is seen from the absorption coefficients, and two obvious structural transformations are also observed at 50 GPa and 100 GPa, respectively.