Optimally Tuned Multiconfigurational Short-Range DFT for Linear Response Properties

Fuente: arXiv
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Main Authors: Hapka, Michał, Pernal, Katarzyna, Pastorczak, Ewa
Format: Preprint
Published: 2026
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author Hapka, Michał
Pernal, Katarzyna
Pastorczak, Ewa
author_facet Hapka, Michał
Pernal, Katarzyna
Pastorczak, Ewa
contents Multiconfigurational short-range density functional theory (MC-srDFT) rigorously combines ground state wavefunction theory with DFT. Unlike single-reference range-separated hybrid functionals, MC-srDFT has lacked theoretically grounded protocols for choosing the system-specific range-separation parameter. To address this problem, we introduce an optimal-tuning scheme based on enforcing the correct exponential decay of the electron density. We show that the range-separation parameter can be determined from the ionization potential given by the smallest-magnitude eigenvalue of the Extended Koopmans' Theorem matrix constructed for the model Hamiltonian. We validate this approach for static and dynamic dipole polarizabilities of ground-state molecular systems using MC-srDFT within both full linear response and its extended random phase approximation (ERPA) variant. Optimal tuning substantially improves polarizabilities relative to the commonly used universal $μ= 0.4\,\mathrm{bohr}^{-1}$ parameter.
format Preprint
id arxiv_https___arxiv_org_abs_2603_04106
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Optimally Tuned Multiconfigurational Short-Range DFT for Linear Response Properties
Hapka, Michał
Pernal, Katarzyna
Pastorczak, Ewa
Chemical Physics
Multiconfigurational short-range density functional theory (MC-srDFT) rigorously combines ground state wavefunction theory with DFT. Unlike single-reference range-separated hybrid functionals, MC-srDFT has lacked theoretically grounded protocols for choosing the system-specific range-separation parameter. To address this problem, we introduce an optimal-tuning scheme based on enforcing the correct exponential decay of the electron density. We show that the range-separation parameter can be determined from the ionization potential given by the smallest-magnitude eigenvalue of the Extended Koopmans' Theorem matrix constructed for the model Hamiltonian. We validate this approach for static and dynamic dipole polarizabilities of ground-state molecular systems using MC-srDFT within both full linear response and its extended random phase approximation (ERPA) variant. Optimal tuning substantially improves polarizabilities relative to the commonly used universal $μ= 0.4\,\mathrm{bohr}^{-1}$ parameter.
title Optimally Tuned Multiconfigurational Short-Range DFT for Linear Response Properties
topic Chemical Physics
url https://arxiv.org/abs/2603.04106