Stich Michael, Ribó Josep M, Blackmond Donna G, Hochberg David
Non-linearity and Complexity Research Group, System Analytics Research Institute, School of Engineering and Applied Science, Aston University, B4 7ET Birmingham, United Kingdom.
Department of Organic Chemistry, Institute of Cosmos Science (IEEC-UB), University of Barcelona, Barcelona, Spain.
J Chem Phys. 2016 Aug 21;145(7):074111. doi: 10.1063/1.4961021.
We analyze a recent proposal for spontaneous mirror symmetry breaking based on the coupling of first-order enantioselective autocatalysis and direct production of the enantiomers that invokes a critical role for intrinsic reaction noise. For isolated systems, the racemic state is the unique stable outcome for both stochastic and deterministic dynamics when the system is in compliance with the constraints dictated by the thermodynamics of chemical reaction processes. In open systems, the racemic outcome also results for both stochastic and deterministic dynamics when driving the autocatalysis unidirectionally by external reagents. Nonracemic states can result in the latter only if the reverse reactions are strictly zero: these are kinetically controlled outcomes for small populations and volumes, and can be simulated by stochastic dynamics. However, the stability of the thermodynamic limit proves that the racemic outcome is the unique stable state for strictly irreversible externally driven autocatalysis. These findings contradict the suggestion that the inhibition requirement of the Frank autocatalytic model for the emergence of homochirality may be relaxed in a noise-induced mechanism.
我们分析了最近一项基于一级对映选择性自催化与对映体直接生成的耦合而提出的自发镜像对称破缺提议，该提议认为内在反应噪声起着关键作用。对于孤立系统，当系统符合化学反应过程热力学所规定的约束时，外消旋状态对于随机动力学和确定性动力学而言都是唯一稳定的结果。在开放系统中，当通过外部试剂单向驱动自催化时，随机动力学和确定性动力学也都会产生外消旋结果。只有当逆反应严格为零时，非外消旋状态才会在后者中出现：对于小种群和小体积而言，这些是动力学控制的结果，并且可以通过随机动力学进行模拟。然而，热力学极限的稳定性证明，对于严格不可逆的外部驱动自催化，外消旋结果是唯一的稳定状态。这些发现与如下观点相矛盾，即弗兰克自催化模型中对于同手性出现的抑制要求在噪声诱导机制中可能会放宽。
