Book Image

Quantum Chemistry and Computing for the Curious

By : Keeper L. Sharkey, Alain Chancé
Book Image

Quantum Chemistry and Computing for the Curious

By: Keeper L. Sharkey, Alain Chancé

Overview of this book

Explore quantum chemical concepts and the postulates of quantum mechanics in a modern fashion, with the intent to see how chemistry and computing intertwine. Along the way you’ll relate these concepts to quantum information theory and computation. We build a framework of computational tools that lead you through traditional computational methods and straight to the forefront of exciting opportunities. These opportunities will rely on achieving next-generation accuracy by going further than the standard approximations such as beyond Born-Oppenheimer calculations. Discover how leveraging quantum chemistry and computing is a key enabler for overcoming major challenges in the broader chemical industry. The skills that you will learn can be utilized to solve new-age business needs that specifically hinge on quantum chemistry
Table of Contents (14 chapters)
8
Chapter 8: References
9
Chapter 9:Glossary
Appendix B: Leveraging Jupyter Notebooks on the Cloud
Appendix C: Trademarks

Summary

In this chapter, we have recalled the non-BO molecular Hamiltonian and given an outline of a method for extending the very accurate non-BO calculations with ECGs to states where the diatomic molecule is excited to the first rotational state and also vibrationally excited to an arbitrary level. We have shown a vibrational frequency analysis calculation with Psi4 of the carbon dioxide molecule. We have presented the vibrational spectra for ortho-para isomerization of hydrogen molecules calculated with a non-BO method [Sharkey], with a BO method [Komasa], and their comparison with experimental data. The non-BO method is highly accurate in predicting all states, including excited states of the hydrogen molecule. The scaling of the wave functions used for both BO and non-BO methods has a factorial dependence and is considered an NP-hard problem.