%A Wen-Ji Shen(沈文吉), Tian-Xiao Liang(梁天笑), Zhao Liu(刘召), Xin Wang(王鑫), De-Fang Duan(段德芳), Hong-Yu Yu(于洪雨), and Tian Cui(崔田) %T Structural evolution and molecular dissociation of H2S under high pressures %0 Journal Article %D 2022 %J Chin. Phys. B %R 10.1088/1674-1056/ac5980 %P 76102-076102 %V 31 %N 7 %U {https://cpb.iphy.ac.cn/CN/abstract/article_124919.shtml} %8 2022-06-09 %X Solid H$_{2}$S as the precursor for H$_{3}$S with incredible superconducting properties under high pressure, has recently attracted extensive attention. Here in this work, we propose two new phases of H$_{2}$S with $P$4$_{2}/n$ and $I$4$_{1}/a$ lattice symmetries in a pressure range of 0 GPa-30 GPa through first-principles structural searches, which complement the phase transition sequence. Further an $ab initio$ molecular dynamics simulation confirms that the molecular phase $P2/c$ of H$_{2}$S is gradually dissociated with the pressure increasing and reconstructs into a new $P$2$_{1}/m$ structure at 160 GPa, exhibiting the superconductivity with $T_{\rm c}$ of 82.5 K. Our results may provide a guidance for the theoretical study of low-temperature superconducting phase of H$_{2}$S.