Ivić Zoran, Zeković Slobodan, Kostić Dragan
The Vinca Institute of Nuclear Sciences, Theoretical Physics Department, 020 11001 Belgrade, Serbia, Yugoslavia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2002 Feb;65(2 Pt 1):021911. doi: 10.1103/PhysRevE.65.021911. Epub 2002 Jan 25.
We report the results of theoretical examinations of large polaron motion in one-dimensional (1D) molecular crystals under the influence of thermal fluctuations of the host lattice and constant electric field. Such a situation may arise in biological macromolecules such as an alpha helix where charge (electron) transfer may be achieved by a polaron (soliton) mechanism. In that case, the electric field represents the effective endogenous electric field which is always present in realistic conditions. We derive and solve the Fokker-Planck equation for the distribution function of the soliton's center-of-mass position. It is shown that the soliton effectively exhibits a random walk. Moreover, in order to examine statistical properties of the soliton wave function, we calculate the mean value of the soliton probability density: </beta(x,t)/(2)> and we find that, for sufficiently large times, thermal fluctuations destruct the soliton, which transforms into the Gaussian packet. These results were used in order to estimate the relevance of the soliton model of charge transfer in polypeptide chains.
我们报告了在主体晶格热涨落和恒定电场影响下，一维（1D）分子晶体中大型极化子运动的理论研究结果。这种情况可能出现在生物大分子中，如α螺旋，其中电荷（电子）转移可能通过极化子（孤子）机制实现。在这种情况下，电场代表现实条件中始终存在的有效内源性电场。我们推导并求解了孤子质心位置分布函数的福克 - 普朗克方程。结果表明，孤子有效地表现出随机游走。此外，为了研究孤子波函数的统计特性，我们计算了孤子概率密度的平均值：<β(x,t)/(2)>，并且发现，在足够长的时间后，热涨落会破坏孤子，使其转变为高斯包。这些结果被用于估计多肽链中电荷转移的孤子模型的相关性。
