238 citations · 627 across the 19 of their papers we have counts for
10 papers · 1 filter
CIS(2): a state-specific, size-intensive perturbative correction to configuration interaction singles
Takashi Tsuchimochi
We present a state-specific second-order perturbation theory based on a configuration interaction singles (CIS) reference and its generalized Fock operator. Starting from a fully i…
Analytical Nuclear Gradients for State-Averaged Configuration Interaction Singles Variants: Application to Conical Intersections
Takashi Tsuchimochi
We derive analytical nuclear gradients for state-averaged orbital-optimized configuration interaction singles (SACIS) and its spin-projected extension (SAECIS), enabling efficient…
TDSCF: Time-Dependent Density Functional Theory with a Non-Aufbau Reference for near-degenerate states
Shuto Shibasaki, Fumiya Mohri, Takashi Tsuchimochi
Near-degenerate electronic structures remain a major challenge for conventional single-reference density functional theory (DFT). To address this problem, we propose time-dependent…
Leveraging configuration interaction singles for qualitative descriptions of ground and excited states: state-averaging, linear-response, and spin-projection
Takashi Tsuchimochi, Benjamin Mokhtar
While configuration interaction singles (CIS) provides a computationally efficient description of excited states, it systematically overestimates excitation energies and performs p…
Double Configuration Interaction Singles: Scalable and size-intensive approach for orbital relaxation in excited states and bond-dissociation
Takashi Tsuchimochi
We present a novel theoretical scheme for orbital relaxation in configuration interaction singles (CIS) based on a perturbative treatment of its electronic Hessian, whose analytica…
Many-Body-Expansion Based on Variational Quantum Eigensolver and Deflation for Dynamical Correlation
Enhua Xu, Yuma Shimomoto, Seiichiro L. Ten-no +1
In this study, we utilize the many-body expansion (MBE) framework to decompose electronic structures into fragments by incrementing the virtual orbitals. Our work aims to accuratel…
Spin-projection for quantum computation: A low-depth approach to strong correlation
Takashi Tsuchimochi, Yuto Mori, Seiichiro L. Ten-no
Although spin is a core property in fermionic systems, its symmetry can be easily violated in a variational simulation, especially when strong correlation plays a vital role therei…
Bridging single- and multireference domains for electron correlation: spin-extended coupled electron pair approximation
Takashi Tsuchimochi, Seiichiro Ten-no
We propose a size-consistent generalization of the recently developed spin-extended configuration interaction with singles and doubles (ECISD), where a CI wave function is explicit…
General technique for analytical derivatives of post-projected Hartree-Fock
Takashi Tsuchimochi, Seiichiro Ten-no
In electronic structure theory, the availability of analytical derivative is one of the desired features for a method to be useful in practical applications, as it allows for geome…
Configuration interaction combined with spin-projection for strongly correlated molecular electronic structures
Takashi Tsuchimochi, Seiichiro Ten-no
We introduce single and double particle-hole excitations in the recently revived spin-projected Hartree-Fock. Our motivation is to treat static correlation with spin-projection and…