Do Computed Crystal Structures of Nonpolar Molecules Depend on the Electrostatic Interactions? The Case of Tetracene

详细信息    查看全文

• 作者：Raffaele Guido Della Valle ; Elisabetta Venuti ; Aldo Brillante ; Alberto Girlando
• 刊名：Journal of Physical Chemistry A
• 出版年：2008
• 出版时间：February 7, 2008
• 年：2008
• 卷：112
• 期：5
• 页码：1085 - 1089
• 全文大小：101K
• 年卷期：v.112,no.5(February 7, 2008)
• ISSN：1520-5215

文摘

We present a strategy for comparing the global properties of competing potential models. By systematicallysampling the potential energy surface of crystalline tetracene, we assess how the number, energy and structureof its minima are modified by switching on (or off) the Coulombic interactions. The increased complexity ofthe Coulombic potential leads to a more "rugged" potential energy surface with a larger number of minima,but the effect is not large. In fact, we find a subset of minima stable only in presence of the Coulombicinteractions, a smaller subset stable only in their absence, and a large majority stable in both cases. Amongthese, there is a very good, but not perfect, correlation between the energies and the structures computed withand without the electrostatic interactions. Although electrostatic interactions play a role even in a rigid nonpolarmolecule such as tetracene, they are not as crucial as often believed, because altering the electrostatic model(or switching it off completely) leads, in most cases, to equivalent results.