分子磁体中量子-经典渡越的数值研究

运用数值的方法研究了分子磁体的隧穿效应中量子-经典渡越问题.从双轴磁晶各向异性模型出发,计算了不同参数下各能级的隧穿率随能量以及温度的变化关系,直观地描述了从量子隧穿到经典热跳跃渡越的物理过程,并描述了最佳隧穿位置在不同参数下随温度的变化行为.研究发现,数值计算结果和解析结果是相吻合的,验证了在此渡越过程中确实存在一级转变与二级转变,并提出检验一级转变的可能性.

A NUMERICAL STUDY ON QUANTUM-CLASSICAL CROSSOVER IN MOLECULE-MAGNETS

The quantum-classical crossover in the tunneling effect of molecule-magnels is studied by means of numerical method. From anisotropic biaxial magnetocrystalline the transition rate of energy and temperature for different parameters is calculated numerically. The transition rate of energy and temperature for different physical process from quantum tunneling to thermal hopping, as well as the behavior of the optimal transition position varying as temperature for different parameters are carefully studied. The numerical results are in good agreement with analytic results, which show a clear indication of the existence of the first-order and secondorder transitions in quantum-classical crossover. The way to test first-order transition is also discussed.