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DOE OSTI · 2427984

Analytic gradients for compressed multistate pair-density functional theory

Bao, Jie J.·Hermes, Matthew R.·Scott, Thais R.·Sand, Andrew M.·Lindh, Roland·Gagliardi, Laura·Truhlar, Donald G.
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Abstract

Photochemical reactions often involve states that are closely coupled due to near degeneracies, for example by proximity to conical intersections. Therefore, a multistate method is used to accurately describe these states; for example, ordinary perturbation theory is replaced by quasidegenerate perturbation theory. Multiconfiguration pair-density functional theory (MC-PDFT) provides an efficient way to approximate the full dynamical correlation energy of strongly correlated systems, and we recently proposed compressed multistate pair-density functional theory (CMS-PDFT) to treat closely coupled states. In the present paper, we report the implementation of analytic gradients for CMS-PDFT in both OpenMolcas and PySCF, and here we illustrate the use of these gradients by applying the method to the excited states of formaldehyde and phenol.

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74 ATOMIC AND MOLECULAR PHYSICSanalytic gradientselectronic structure methodexcited statesmolecular geometrypair-density functional theory

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Bao, Jie J., Hermes, Matthew R., Scott, Thais R., Sand, Andrew M., Lindh, Roland, Gagliardi, Laura, Truhlar, Donald G.. 2022-09-06. Analytic gradients for compressed multistate pair-density functional theory. https://doi.org/10.1080/00268976.2022.2110534

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