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Angle-resolved polarized (ARP) Raman spectroscopy can be utilized to characterize the Raman modes of two-dimensional layered materials based on crystal symmetry or crystal orientation. In this paper, the polarization properties of E 1 2 g and A1g modes on the basal plane and edge plane of high purity 2H-MoS2 bulk crystal grown by chemical vapor transport (CVT) method were investigated by ARP Raman spectroscopy. The I and II type ARP Raman spectroscopy with four kinds of polarization configurations: αY, αX, βY, and βX were used to explore the intensity dependence of E 1 2 g and A1g modes at different planes on the polarization direction of incident/scattered light. The results show that the E 1 2 g and A1g modes exhibit different polarization properties dependent on the polarization of the incident laser and the in-plane rotation of the sample at different planes. The experimental results were confirmed and analyzed through theoretical calculation. Our work sheds light on the intriguing effect of the subtle atomic structure in stacked MoS2 layers on the resulting ARP Raman properties. This provides a reference for the study of other two-dimensional layered crystalline materials by ARP Raman spectroscopy.

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We extract the e + e − → π + π − cross section in the energy range between 600 and 900 MeV, exploiting the method of initial state radiation. A data set with an integrated luminosity of 2.93 fb −1 taken at a center-of-mass energy of 3.773 GeV with the BESIII detector at the BEPCII collider is used. The cross section is measured with a systematic uncertainty of 0.9%. We extract the pion form factor |F π | 2 as well as the contribution of the measured cross section to the leading-order hadronic vacuum polarization contribution to (g −2) μ. We find this value to be a ππ,LO μ (600-900 MeV) = (368.2 ±2.5 stat ±3.3 sys) •10 −10 , which is between the corresponding values using the BaBar or KLOE data.