分子间费米共振增强二元溶液体系的受激拉曼散射研究

Enhanced stimulated Raman scattering of binary solution by intermolecular Fermi resonance

研究了液芯光纤内不同体积比的甲苯和间二甲苯二元混合溶液的受激拉曼散射.实验结果表明:在不同的体积比之下二元溶液的环呼吸振动模式1002cm-1,甲基的CH伸缩振动模式2920cm-1以及芳香环CH对称伸缩振动模式3058cm-1的拉曼带同时产生受激拉曼辐射,并且2920cm-1和3058cm-1拉曼带的一阶受激拉曼散射阈值要低于1002cm-1拉曼带的二阶阈值;同时随着体积比的不同2920cm-1和3058cm-1拉曼带的主峰位置也随之改变.通过拉曼散射截面理论验证了分子间费米共振是导致上述现象的主要原因.

Stimulated Raman scattering（SRS） of binary solution of toluene and m-xylene are studied at different volume concentrations in liquid-core optical fiber. The experimental results show that the vibration modes of 1002 cm-1, 2920 cm-1 and 3058 cm-1 bands are simultaneously stimulated to generate the SRS, and the SRS thresholds of the 1st-order Stokes of 2920 cm-1 and 3058 cm-1 bands are lowered compared with the 2nd-order Stokes of 1002 cm-1 band, and the main peaks of 2920 cm-1 and 3058 cm-1 bands are different as volume concentration changes. We assume that the intermolecular Fermi resonance is the main mechanism for these phenomena, which is explained by the Raman scattering cross section theory.