中文摘要：

手性丙氨酸单晶的极性N＋H…O氢键在～270K的自发对称性破缺,可用变温拉曼振动光谱在b（cc）b几何条件下在线测定.由于其对手性的灵敏度,可以测定D-和L-丙氨酸的N＋H…O氢键在电子自旋翻转相变时的微小能差.晶体定向能量的正/负,在于电子自旋的上/下转向,取决于原子内在磁场的方向.变温拉曼振动光谱可以观察到：在D-和L-丙氨酸单晶之间,拉曼散射光子的波数位移方向相反,散射光子的不对称度约为1/3.由于自旋是轴矢量,样品必须是单晶,沿轴向测定.多晶粉末不能观察到相变.与次甲基（Cα-H）在260K的自旋翻转相变,用变温拉曼振动光谱在c（aa）c几何条件下的相对测量结果接近一致.本实验提供了一条证明真实手性和＂宇称-时间（PT）不对称＂的新线索.

英文摘要：

Spontaneous symmetry breaking of the N ＋ H…O bond in chiral alanine crystals around 270 K was detected in situ by Raman vibrational scattering with b（cc）b geometry.An electron spin-flip transition of the N ＋ H…O mode in D-/L-alanine was observed by the scattering of light with left/right orientation and its spin projection antiparallel to the direction of propagation.It is an internal magnetic field originated from the spin-orbit interaction.An obvious Raman wavenumber shift with opposite in sign and roughly one third of the asymmetry （A） of the scattered photon between D-and L-alanine crystals was observed.This shift was not seen in polycrystalline powder measurements because spin is an axial vector.An electron spin-flip transition of the methyne （C α-H） mode around 260 K was shown to be approximative coincidence by examining the temperature-dependent relative intensity of asymmetric Raman scattering with c（aa）c geometry.This article provides evidence for the true chirality and parity-time （PT） asymmetry in molecular clusters of D-and L-alanine crystals.