Siódmiak Jacek
Institute of Mathematics and Physics, Faculty of Chemical Technology and Engineering, Bydgoszcz University of Science and Technology, Al. Prof. S. Kaliskiego 7, 85-796 Bydgoszcz, Poland.
Entropy (Basel). 2024 Feb 28;26(3):214. doi: 10.3390/e26030214.
In the case of certain chemical compounds, especially organic ones, electrons can be delocalized between different atoms within the molecule. These resulting bonds, known as resonance bonds, pose a challenge not only in theoretical descriptions of the studied system but also present difficulties in simulating such systems using molecular dynamics methods. In computer simulations of such systems, it is often common practice to use fractional bonds as an averaged value across equivalent structures, known as a resonance hybrid. This paper presents the results of the analysis of five forms of C fullerene polymorphs: one with all bonds being resonance, three with all bonds being integer (singles and doubles in different configurations), one with the majority of bonds being integer (singles and doubles), and ten bonds (within two opposite pentagons) valued at one and a half. The analysis involved the Shannon entropy value for bond length distributions and the eigenfrequency of intrinsic vibrations (first vibrational mode), reflecting the stiffness of the entire structure. The maps of the electrostatic potential distribution around the investigated structures are presented and the dipole moment was estimated. Introducing asymmetry in bond redistribution by incorporating mixed bonds (integer and partial), in contrast to variants with equivalent bonds, resulted in a significant change in the examined observables.
对于某些化合物，特别是有机化合物，电子可以在分子内的不同原子之间离域。这些形成的键，即共振键，不仅在研究体系的理论描述中构成挑战，而且在使用分子动力学方法模拟此类体系时也存在困难。在对此类体系的计算机模拟中，通常的做法是使用分数键作为等效结构的平均值，即所谓的共振杂化体。本文展示了对五种形式的C富勒烯多晶型的分析结果：一种所有键均为共振键，三种所有键均为整数键（单键和双键处于不同构型），一种大部分键为整数键（单键和双键），以及十个键（在两个相对的五边形内）的值为一点五。分析涉及键长分布的香农熵值和本征振动的本征频率（第一振动模式），反映了整个结构的刚度。展示了所研究结构周围的静电势分布图，并估算了偶极矩。与具有等效键的变体相比，通过纳入混合键（整数键和部分键）引入键重新分布的不对称性，导致所检查的可观测量发生了显著变化。
