By Willow Candage, Charlea Kimbleton, Owen White

Faculty Mentor: Leanna Giancarlo

Abstract

The bond length and bond dissociation energy for a molecule play an important role in the thermodynamic properties of that molecule. Both the equilibrium bond length and the bond dissociation energy of a molecule can be determined from its potential energy curve. One way to establish a potential energy curve for a molecule is by using computational chemistry. To accomplish this for the dihydrogen molecule, the computational software GAMESS was utilized to measure the electronic energy associated with the molecule at 28 different bond lengths ranging from 0.25 to 7.0 angstroms (A). From these a potential energy curve was constructed by plotting the potential energy, V(x), in kJ/mol versus the bond length in A. Using this potential energy curve, the equilibrium bond length for dihydrogen was determined to be 0.75 A, which has a percent error of 1.35% when compared to literature values of 0.74 A. The well depth for dihydrogen was also determined to be 1025.5 kJ/mol, which is significantly higher than the literature value of 462 kJ/mol. Raman spectroscopy was then used to further evaluate the zero point energy (ZPE). To improve and expand upon these preliminary results, further research will be conducted by adjusting the computational parameters, specifically the type of basis set, of the potential energy calculations to decrease the error in both the bond length and dissociation energy of dihydrogen. Changing the basis set for the calculation to a more accurate ab initio, set such as SPK-DZP, should increase the accuracy of the computations.