Charge-regulation phase transition on surface lattices of titratable sites adjacent to electrolyte solutions: An analog of the Ising antiferromagnet in a magnetic field.
Charge-regulation phase transition on surface lattices of titratable sites adjacent to electrolyte solutions: An analog of the Ising antiferromagnet in a magnetic field.
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邻近电解质溶液的可滴定位点表面晶格上的电荷调节相变：磁场中伊辛反铁磁体的类似物。
DOI：
10.1103/physreve.92.062123
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
Thurston,GeorgeM
中科院分区：
文献类型：
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作者：
Shore,JoelD;Thurston,GeorgeM
我们报告的电荷图案相变的二维正方形晶格的可滴定的网站，在这里被视为质子化的网站，放置在一个低介电介质的平面界面下面的这种介质和盐溶液。我们使用线性Debye-Hückel模型计算晶格的充电功矩阵，作为占位模式分布的巨正则配分函数的输入。对于一个大范围的参数值，该模型表现出一个近似的逆三次幂律减少的电压产生的单个电荷，作为其在晶格分离的功能，从相邻的可滴定的网站。因此，电荷耦合电压使质子结合的局部概率偏置，该局部概率是除了最近的那些之外的许多邻居的位点的占用率的函数。我们发现，即使在这些较长范围的相互作用的存在下，网站的耦合引起的相变中的网站occupancy表现出交替，棋盘图案，这是一个模拟的反铁磁有序。每单位电荷的正则电荷耦合电压的总强度是德拜长度、电荷深度、Bjerrum长度以及介质和溶剂的介电系数的函数。交替占据跃迁发生在平面上热力学临界点的曲线上方，该曲线代表伊辛反铁磁体的内尔温度变化的电荷调节模拟，作为施加的均匀磁场的函数。反铁磁问题中均匀磁场的模拟是和的组合，和是反铁磁问题中温度的模拟。我们使用Monte Carlo模拟研究的可滴定的网站，包括相互作用的第37最近的邻居类别（一个距离offlattice常数）的占用模式，第一次验证模拟通过比较与最近的邻居的情况下的精确和近似的结果。然后，我们使用模拟映射的电荷图案相边界在theplane。确定的物理参数提供了一个框架，用于识别和设计真实的表面，可以表现出电荷图案相变。
We report a charge-patterning phase transition on two-dimensional square lattices of titratable sites, here regarded as protonation sites, placed in a low-dielectric medium just below the planar interface between this medium and a salt solution. We calculate the work-of-charging matrix of the lattice with use of a linear Debye-Hückel model, as input to a grand-canonical partition function for the distribution of occupancy patterns. For a large range of parameter values, this model exhibits an approximate inverse cubic power-law decrease of the voltage produced by an individual charge, as a function of its in-lattice separation from neighboring titratable sites. Thus, the charge coupling voltage biases the local probabilities of proton binding as a function of the occupancy of sites for many neighbors beyond the nearest ones. We find that even in the presence of these longer-range interactions, the site couplings give rise to a phase transition in which the site occupancies exhibit an alternating, checkerboard pattern that is an analog of antiferromagnetic ordering. The overall strengthof this canonical charge coupling voltage, per unit charge, is a function of the Debye length, the charge depth, the Bjerrum length, and the dielectric coefficients of the medium and the solvent. The alternating occupancy transition occurs above a curve of thermodynamic critical points in theplane, the curve representing a charge-regulation analog of variation of the Néel temperature of an Ising antiferromagnet as a function of an applied, uniform magnetic field. The analog of a uniform magnetic field in the antiferromagnet problem is a combination ofand, andis the analog of the temperature in the antiferromagnet problem. We use Monte Carlo simulations to study the occupancy patterns of the titratable sites, including interactions out to the 37th nearest-neighbor category (a distance oflattice constants), first validating simulations through comparison with exact and approximate results for the nearest-neighbor case. We then use the simulations to map the charge-patterning phase boundary in theplane. The physical parameters that determineprovide a framework for identifying and designing real surfaces that could exhibit charge-patterning phase transitions.