The paper presents amended basic map of states of chemical systems in discrete thermodynamics of chemical equilibria. Uniting two previously found basic map types in one and covering a wider range of situations, it allows us to obtain more detailed pictures and deeper understanding of what is the general chemical system response to the external impact. Amended in this work general expression allows for more flexibility in the response treatment. Graphical solutions to the map, bifurcation diagrams, contain the monostable thermodynamic branch prior to and the bi-stable area after the bifurcation point. On the static diagrams the first consists of two areas - true thermodynamic equilibrium and open equilibrium; the first area is skipped on the dynamic diagrams. In the bi-stable area, the system stresses, caused by further increase of the external impact, discharge themselves through chaotic oscillations, enveloped by two bifurcation sub-branches. Now bifurcation diagrams, corresponding to the amended map, are essentially closer to some experimental graphs, obtained, for instance, in experiments with electrochemical systems.
Chemical reactions induced by oscillating external fields in weak thermal environments
化学反应速率必须在外部刺激控制下进化的系统中越来越多地被确定。在这些系统中,当反应物群体通过来自随时间变化的外部场的强制而被诱导越过能垒时,反应在从反应物到产物的转化期间必须经过的过渡态不再是固定的几何结构,而是时间依赖的。对于周期性受迫模型反应,我们发展了一个附着在过渡态轨道上的无交叉分界面[T。巴奇河Hernandez和T. Uzer,Phys. Rev. Lett. 95,058301(2005)]。我们以前已经表明,对于单模正弦驱动,时变过渡态的稳定性直接决定了反应速率[G. T. Craven,T. Bartsch和R. Hernandez,J.Chem.Phys.141,041106(2014)]。在这里,我们将我们以前的工作扩展到多模驱动波形的情况。通过稳定性分析预测的速率和通过反应通量的数值计算获得的速率之间观察到极好的一致性。我们还表明,最佳分割面和由此产生的反应速率的反应系统驱动的弱热噪声可以近似使用的过渡态几何的基本确定性系统。只要热驱动强度小于周期性驱动的量级,这种一致性就持续存在。这个结果的力量在于它的简单性。在周期性场驱动的化学反应中,与时间相关的无噪声几何获得过渡态理论速率的令人惊讶的准确性揭示了动力学,而不需要蛮力计算的成本。
Tuning bimolecular chemical reactions by electric fields
我们开发了一种理论方法来解决量子力学反应散射问题的存在下的外部领域的基础上的超球坐标描述的反应配合物结合总角动量表示的碰撞在外部领域。该方法使我们能够得到电场中LiF + H -> Li + HF化学反应的收敛结果。我们的计算表明,通过诱导不同的总角动量的状态之间的耦合,电场与幅度<150 kV/cm引起的共振散射和显着修改的总反应几率,产品状态分布和分支比的反应与非弹性散射。
Manipulation of Diatomic Molecules with 'Oriented External Electric Fields': Linear Correlations in Atomic Properties Lead to Non-Linear Molecular Responses
On Exact analytical calculations of thermodynamic functions of gaseous substances, R. Khordad, A. Avazpour, and A. Ghanbari, Chemical Physics 517 (2019) 30
Asymptotic Limit-cycle Analysis of Oscillating Chemical Reactions
研究了振荡化学反应数学模型的渐近极限环分析。本文在简要介绍了应用于偏置Van der Pol振子的数学模型后,考虑了二氧化氯碘丙二酸(CIMA)反应的二维模型和Belousov-Zhabotinsky(BZ)反应的三维和二维Oregonator模型。给出了这些化学反应弛豫振荡周期的显式解析表达式,其精确度在数值的5%以内。在二维CIMA和Oregonator模型中,我们还推导出了导致鸭式爆炸和内爆的临界参数值。