Quantum Mechanical Calculations for Diatomic
Nitrogen, Dimethyl Peroxide, and O-Xylene
Lindsey Westphal and Holleigh Graminske
Abstract:
Multiple molecular properties for diatomic nitrogen, dimethly
peroxide, and o-xylene were calculated including vibrational
energies, electrostatic potentials, dipole moments, partial
charges, highest occupied molecular orbitals(HOMO) and
lowest unoccupied molecular orbitals (LUMO). Different levels of
theory were used, but the best geometry was used for the
calculations.
Introduction:
Molecular orbitals
reflect molecular structure and explain some experimental
characteristics caused by electron location. Basic molecular
structure was determined in the program Avogadro with
its solution being input into the program MacMolPlt to
optimize the molecular geometry. The program GamessQ was
utilized to run quantum mechanical basis sets. Basis sets were used
for intense quantum calculations as it is capable of computing
molecular bond lengths,electrostatic
potentials,
vibrations, etc. The molecules were run through one basis set
to get general improvement and to decrease the calculation
time before being fed into the next basis set in the following
order: 3-21G,
6-21G, 6-31G, and DZV.Each subsequent basis set refined the
molecular structure with energy minimization being the
objective. The program Jmol allowed thevisualization of the calculations produced by
GamessQ.
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