C60分子在有序-无序和玻璃态相变间的取向概率与弛豫行为

用极限动力学模型研究了Ｃ₆₀分子在有序-无序相变和玻璃态相变温度区间取向 角为98°和38°的取向概率与温度的关系.计算结果在玻璃态相变点附近的85K，90K和有序- 无序相变点的260K分别与实验值相吻合，取向概率对实验值更精确的拟合及其对温度的二阶 导数预言玻璃态相变点在84K.导出了弛豫规律，其结果表明：双能级的Ｃ₆₀分子从非平衡态到平衡态的弛豫行为与非指数因子β有关，其总的弛豫时间决定于其中一个较 短的弛豫时间，展宽指数形式保持不变.讨论了KWW方程的非 关键词： 60')" href="#">Ｃ₆₀ 取向概率 非平衡态弛豫

ORIENTATIONAL POPULATION AND RELAXATION BEHAVIOR OF C60 MOLECULES BET WEEN ORDER-DISORDER PHASE TRANSITION AND GLASSY TRANSITION

The site occupancies of orientational angle 98° and 38° of C₆₀ mole cules versus temperature is investigated by extremal dynamic model in the temper ature range between order-disorder phase transition and glassy transition.The oc cupancy of orientational angle 38° calculated by the model are precisely coinci dent with reported experimental values at T=85K,90K and 260K,respectively.The mo re precise agreement and second-order differential to temperature of site occupa ncy predict that the glassy transition point is at 84K.The relaxation process of two orientational states from non-equilibrium deduced by the new model is relat ed to the non-exponent factor β in KWW equation,and overall relaxation of C₆₀ crystal is mainly attributed to the relaxation of the lowest energy le vel.Considering two energy levels and their energy difference,the calculated β value 0.9495 is near the experimental value 0.94±0.02.