James E. T. Smith, Ph.D.

I'm a Flatiron Research Fellow in the Center for Computational Quantum Physics at the Flatiron Institute interested in developing more efficient and robust algorithms for quantum chemistry. For a detailed description of my experience please see my CV.


Generally speaking, my research focuses on two areas: 1) developing highly accurate methods for small to medium sized molecules and 2) maintaining and supporting the open source quantum chemistry package PySCF. All of my projects involve a substantial amount of programming and I spend a lot of time studying and improving the performance of software.

High Accuracy Quantum Chemistry

In graduate school, I worked on methods to treat "strong correlation", which often occurs in chemical systems involving transition metals, bond breaking, or electronic excitations. In systems likes these, we have to turn to expensive wave function based methods like CASSCF. To apply these methods to larger and more complex (i.e. realistic) systems, I helped develop more efficient approximate methods that yield accurate results at a greatly reduced cost.

Below are some of the systems I worked with. Try moving them around with your mouse, they're interactive!


More on this soon!


  1. Samuel M. Greene, Robert J. Webber, James E. T. Smith, Jonathan Weare, Timothy C. Berkelbach. "Full Configuration Interaction Excited-State Energies in Large Active Spaces from Randomized Subspace Iteration". (2022). arXiv
  2. James E. T. Smith, Joonho Lee, Sandeep Sharma. "Nuclear Gradients of Near-Exact Complete Active Space Self-Consistent Field Wave Functions". (2022). arXiv Code


  1. Wyatt Zagorec-Marks, James E. T. Smith, Madison M. Foreman, Sandeep Sharma, J. Mathias Weber. "Intrinsic Electronic Spectra of Cryogenically Prepared Protoporphyrin IX Ions in Vacuo – Deprotonation-Induced Stark Shifts". Physical Chemistry Chemical Physics (2020) 22, 20295-20302. DOI Code
  2. Qiming Sun, Xing Zhang, Samragni Banerjee, Peng Bao, Marc Barbry, Nick S. Blunt, Nikolay A. Bogdanov, George H. Booth, Jia Chen, Zhi-Hao Cui, Janus Juul Eriksen, Yang Gao, Sheng Guo, Jan Hermann, Matthew R. Hermes, Kevin Koh, Peter Koval, Susi Lehtola, Zhendong Li, Junzi Liu, Narbe Mardirossian, James D. McClain, Mario Motta, Bastien Mussard, Hung Q. Pham, Artem Pulkin, Wirawan Purwanto, Paul J. Robinson, Enrico Ronca, Elvira Sayfutyarova, Maximilian Scheurer, Henry F. Schurkus, James E. T. Smith, Chong Sun, Shi-Ning Sun, Shiv Upadhyay, Lucas K. Wagner, Xiao Wang, Alec White, James Daniel Whitfield, Mark J. Williamson, Sebastian Wouters, Jun Yang, Jason M. Yu, Tianyu Zhu, Timothy C. Berkelbach, Sandeep Sharma, Alexander Sokolov, Garnet Kin-Lic Chan. "Recent developments in the PySCF program package". J. Chem. Phys. 153, (2020) 024109. DOI
  3. Joel W. Clancey, Andrew S. Cavanagh, James E. T. Smith, Sandeep Sharma, and Steven M. George. "Volatile Etch Species Produced During Thermal Al2O3 Atomic Layer Etching", J. Phys. Chem. C, 124, (2020) 287-299. DOI
  4. Giuseppe Carleo, Kenny Choo, Damian Hofmann, James E. T. Smith, Tom Westerhout,Fabien Alet, Emily J. Davis, Stavros Efthymiou, Ivan Glasser, Sheng-Hsuan Lin, Marta Mauri, Guglielmo Mazzola, Christian B. Mendl, Evert van Nieuwenburg, Ossian O’Reilly,Hugo Theveniaut, Giacomo Torlai, and Alexander Wietek,"NetKet: A Machine Learning Toolkit for Many-Body Quantum Systems", SoftwareX, 10, (2019) 00311. DOI
  5. Leah G. Dodson, Wyatt Zagorec-Marks, Shuang Xu, James E. T. Smith, J. Mathias Weber, "Intrinsic photophysics of nitrophenolate ions studied by cryogenic ion spectroscopy", Phys. Chem. Chem. Phys. (2018) 28535 - 28543. DOI
  6. James E. T. Smith Bastien Mussard, Adam A. Holmes, Sandeep Sharma, "Cheap and near exact CASSCF with large active spaces", J. Chem. Theor. and Comp. 13 (2017) 5468-5478. (Editor's Choice). DOI arXiv Code
  7. Shuang Xu, James E. T. Smith, Samer Gozem, Anna I. Krylov, J. Mathias Weber. "Electronic Spectra of Tris(2,2'-bipyridine)-M(II) Complex Ions in Vacuo (M = Fe and Os)", Inorg. Chem. 56, (2017) 7029–7037. DOI
  8. Shuang Xu, James E. T. Smith, J. Mathias Weber, "UV Spectra of Tris(2,2'-bipyridine)-M(II) Complex Ions in Vacuo (M = Mn, Fe, Co, Ni, Cu, Zn)", Inorg. Chem. 55 (2016) 11937–11943. DOI
  9. S. Xu, James E. T. Smith, J. M. Weber, "Hydration of a Binding Site with Restricted Solvent Access – Solvatochromic Shift of the Electronic Spectrum of a Ruthenium Polypyridine Complex, One Molecule at a Time", J. Phys. Chem. A, 120 (2016) 7650–7658. DOI
  10. Shuang Xu, James E. T. Smith, J. Mathias Weber, "The Electronic Spectrum of Cryogenic Ruthenium-Tris-Bipyridine Dications in Vacuo", J. Chem. Phys. 145 (2016) 024304. DOI
  11. Shuang Xu, James E. T. Smith, J. Mathias Weber, "Ligand Influence on the Electronic Spectra of Dicationic Ruthenium-Bipyridine-Terpyridine Complexes", J. Phys. Chem. A 120 (2016) 2350–2356. DOI



I contribute to a number of open source software projects.

Name Description
PySCF An accessible Python package for quantum chemistry.
Dice Implementation of the heat-bath configuration interaction (HCI) algorithm for strongly correlated quantum chemistry calculations.
FRI-CC The fast randomized iteration algorithm applied to coupled cluster methods.