磁性高分子链的磁性质和构象性质的Monte Carlo模拟

采用退火 (Annealing)MonteCarlo方法 ,从高温到低温顺序模拟了简立方格点上考虑最近邻Ising相互作用的磁性高分子链在不同温度的磁性质和构象性质 .磁性高分子链在低温下存在自发磁矩 ,无限长链的临界温度Tc=1 77± 0 0 5J kB.在临界温度附近 ,高分子链经历了从伸展的无规线团到紧缩球体的塌缩相变 .对链的尺寸、形状、近邻数及能量的分析表明 ,高分子链的构象性质从温度Tc=1 77开始发生较明显的变化 ,这表明高分子Ising链的相变是Ising相互作用和链节运动协同作用的结果 .

MONTE CARLO STUDY ON MAGNETIC AND CONFIGURATIONAL PROPERTIES OF MAGNETIC POLYMER CHAINS

The magnetic and configurational properties of Ising polymer chains on simple cubic lattice are simulated using annealing Monte Carlo technique.Spontaneous magnetization at low temperature is found for magnetic polymers,and the critical temperature is estimated as T c = 1 77±0 05(J/k B) for long chains.At T c,the chain also undergoes a collapse transition from a random coil at high temperature to a compacted globule at low temperature.For all simulated chain lengths,it is found that the configurational properties change very little above T c but obviously below T c.The analysis of chain dimension,shape,nearest neighbor number as well as energy shows that the phase transition of Ising polymer chains results from the cooperation of segment movement and Ising interaction.