The Effect of Basis Set on Quantum Tunneling Probability with the Case of trans-HCOH Isomerization

Abstract

We investigate the effects of basis set in quantum tunneling probability in the case of trans-HCOH isomerization to H2CO. Based on Density Functional Theory (DFT) calculation with B3LYP as functional exchange-correlation and 6-31G(d, p) as basis set, Rizka et al. found that trans-HCOH molecule has half life for 2.5 hours. The result has 0.7 hour longer than experimental result done by Schreiner et al. In this study, we used five variations of basis set which are: STO-3G, 6-31G, 6-31G(d, p), 6-31+G(d, p), and LANL2DZ. We started to investigate the effects of basis set on the electronic structure and vibrational frequency of the molecules. Then, we investigated the effects of basis set on quantum tunneling probability in molecule. Based on quantum tunneling probabilities, we could calculate half-life of trans-HCOH isomerization to H2CO. We compare our results to the experimental result done by Schreiner et al. The results show that basis set increases the quantum tunneling probability of the isomerization.