Orbital contributions to the exchange-repulsion energy of atomic and molecular aggregates

Identifier:  TFG:1707

Handle: https://hdl.handle.net/20.500.11797/TFG1707

Authors:  Miralles Adrover, Gemma

Abstract:
The exchange-repulsion energy (Eexr) has been calculated for horizontal displacements of three different systems: N2-He, Cl2-He and the perylene bisimide (PBI) dimer. The calculations were carried out with different basis sets: TZVP, cc-pVDZ, cc-pVTZ and aug- cc-pVDZ for the two smaller systems and TZVP for the larger system PBI-PBI. The aim of these calculations is to determine the interactions of the orbitals that contribute most to the Eexr. Additionally, the interaction energy contributions between a Helium atom and a N2 as well as a Cl2 molecule were determined with an energy decomposition analysis (EDA). The calculations were performed in horizontal and vertical displacements of the He using HF and DFT methods (in the latter B-LYP was used as functional) together with the same basis set previously mentioned. The purpose of this part was dedicated to studying the contribution of each type of energy to the total interaction energy of the system (Eint). It has been observed that the Eexr has a fair if not the most important contribution to the total energy. Finally, a HF 2D calculation has also been performed too on the N2-He and Cl2-He systems with TZVP as a basis set. Here, energy isocontours have been observed to a better understanding of the interactions of both monomers.