High pressure Raman spectra were measured for 2H–MoS₂ at small pressure intervals, including Stokes Raman spectra from 0 to 40 GPa and anti-Stokes Raman spectra from 0 to 31.4 GPa. Analysis of the pressure-dependent frequencies and full width at half maximums for the A_1g and ${\text{E}}_{2\text{g}}^1$ modes showed that the A_1g mode was more sensitive to pressure. The peaks of the ${\text{E}}_{2\text{g}}^1$ mode split from 20.0 GPa, thereby indicating the beginning of a phase transition from 2H_c to 2H_a, and the transition was complete near 40.7 GPa. In the same pressure range, density functional theory calculations confirmed the phase transition and the pressure-dependent frequencies were in good agreement with the experimental results. Simulations predicted that the linear growth in the frequency of A_1g-2H_c with the pressure was inhibited at 35 GPa by repulsive interlayer interactions, thereby causing frequency splitting from the A_1g-2H_a mode. In addition, the in-plane ${\text{E}}_{2\text{g}}^1$ mode of the 2H_c phase was annihilated when the pressure reached 40.7 GPa. Based on our results and previous research, we propose that the 2H_c-2H_a phase transition of MoS₂ is complete at around 40.7 GPa and this explains the absence of the Raman peak split for the out-of-plane A_1g mode.

在较小的压力间隔内测量了2 H -MoS ₂的高压拉曼光谱，包括0至40 GPa的斯托克斯拉曼光谱和0至31.4 GPa的反斯托克斯拉曼光谱。分析A _1g和A _1g的压力相关频率和半峰全宽${\text{E}}_{\mathrm{2个}\text{G}}^{\mathrm{1个}}$模式显示A _1g模式对压力更敏感。的山峰${\text{E}}_{\mathrm{2个}\text{G}}^{\mathrm{1个}}$模式从20.0 GPa分裂，从而表明从2 H _c到2 H _a的相变开始，并且在40.7 GPa附近完成了相变。在相同的压力范围内，密度泛函理论计算证实了相变和与压力有关的频率与实验结果吻合良好。模拟预测，通过排斥性层间相互作用，在35 GPa时，A _1g -2 H _c的频率随压力的线性增长受到抑制，从而导致频率从A _1g -2 H _a模式分裂。此外，机内${\text{E}}_{\mathrm{2个}\text{G}}^{\mathrm{1个}}$当压力达到40.7 GPa时，2 H _c相的模式消失。根据我们的结果和先前的研究，我们提出MoS ₂的2 H _c -2 H _a相变在40.7 GPa左右完成，这解释了平面外A _1g模式不存在拉曼峰分裂的情况。。