Article
Chemistry, Physical
James E. T. Smith, Joonho Lee, Sandeep Sharma
Summary: This paper studies the application of nuclear gradients of HCISCF wave functions for optimizing molecular geometries. The study shows that HCISCF nuclear gradients are not sensitive to the size of the variational space, reducing computational cost. The method is attractive for studying strongly correlated systems with larger active spaces. The paper also explores the challenges of DFT in realistic catalysts and demonstrates how HCISCF can improve the accuracy of DFT results.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Nils Schieschke, Tilmann Bodenstein, Sebastian Hoefener
Summary: The study incorporates a Fock-operator complete-active space self-consistent field (CAS-SCF) method combined with frozen-density embedding (FDE) into the KOALA quantum-chemistry program, allowing treatment of electronic configurations with different spin states. The efficiency and convergence of the implementation were evaluated using a stretched lithium dimer example, demonstrating its potential for orbital selection in complex environments for CAS methods.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Saad Yalouz, Emiel Koridon, Bruno Senjean, Benjamin Lasorne, Francesco Buda, Lucas Visscher
Summary: In this paper, we introduce several technical and analytical extensions to enhance the efficiency and accuracy of the state-averaged orbital-optimized variational quantum eigensolver (SA-OO-VQE) algorithm. These extensions include an efficient state-resolution procedure and the estimation of gradients and nonadiabatic couplings, which are crucial for practical applications such as conical intersection search and quantum dynamics simulation.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Multidisciplinary
Ying Fuming, Ji Chenru, Su Peifeng, Wu Wei
Summary: The lambda-DFCAS method divides electronic correlation into static and dynamic parts, with the parameter lambda controlling the hybrid extent, providing a multireference density functional theory with size-consistency. Test examples show that the accuracy of lambda-DFCAS is close to CASPT2, with computational cost similar to CASSCF.
CHEMICAL JOURNAL OF CHINESE UNIVERSITIES-CHINESE
(2021)
Article
Chemistry, Physical
Thais R. Scott, Meagan S. Oakley, Matthew R. Hermes, Andrew M. Sand, Roland Lindh, Donald G. Truhlar, Laura Gagliardi
Summary: Density fitting reduces computational cost by avoiding computation and manipulation of four-index electron repulsion integrals, allowing efficient optimization of large systems. The new approach increases computation speed with negligible loss in accuracy, while smaller grid sizes further reduce costs with minimal impact on optimized geometries and gradient values.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Muhammad N. Tahir, Tong Zhu, Honghui Shang, Jia Li, Volker Blum, Xinguo Ren
Summary: We present a method based on localized resolution of identity (LRI) for calculating the analytical gradients of RPA ground-state energy with respect to atomic positions within the atomic orbital basis set framework. Our results demonstrate the numerical precision and usefulness of LRI in RPA gradient evaluations.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Vishikh Athavale, Hung-Hsuan Teh, Yihan Shao, Joseph Subotnik
Summary: We derive and implement analytic gradients and derivative couplings for TDDFT-1D method, and validate its accuracy by comparing with finite difference values. Furthermore, we demonstrate its capability in locating optimized geometries and minimum-energy crossing points along conical seams.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Sascha A. Brueck, Nityananda Sahu, Konstantin Gaul, Robert Berger
Summary: This article describes an analytic gradient approach for computing the derivatives of parity-violating (PV) potentials in chiral molecules with respect to nuclear displacements, implemented within a quasirelativistic mean-field framework. The calculated PV potential gradients are used to estimate PV frequency splittings between enantiomers in rotational and vibrational spectra of four chiral polyhalomethanes. The results show good agreement with previously reported theoretical values in the single-mode approximation. The influence of non-separable anharmonic effects on vibrational frequency shifts, which can be readily estimated with the analytic derivative approach, is also examined.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Chenchen Song
Summary: This paper presents a state-averaged complete active space self-consistent field method in polarizable continuum model (PCM) for studying photoreactions in solvents. The optimization of solute wavefunctions and PCM surface charges of the solvent simultaneously minimizes the state-averaged free energy. The method supports both fixed and dynamic weights, with the weights automatically adjusted based on energy gaps. The paper also discusses the implementation of the method using seven basic operations, allowing for high-performance computation on graphical processing units. Results demonstrating the accuracy and performance of the implementation are presented, along with applications in conical intersection search and photoreaction energy pathways in solvents.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
S. B. Hansen
Summary: Modern density functional theory (DFT) is a powerful tool for predicting material properties in high energy density plasmas, limited to local thermodynamic equilibrium (LTE). We propose a modification to include non-LTE effects and extend DFT-based models. We expand the electronic orbitals to generate detailed electronic structure and opacity spectra.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2023)
Article
Chemistry, Physical
Rebecca Hanscam, Eric Neuscamman
Summary: In this study, a generalized variational principle is employed to enhance the stability and convergence of fully excited-state-specific complete active space self-consistent field theory. The proposed method shows better resistance to root flipping and achieves tighter convergence to an energy stationary point. The ability to optimize orbital shapes for individual excited states is especially important for charge-transfer states and some doubly excited states.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Ernest R. Davidson, Joseph Vincent Ortiz, Viktor N. Staroverov
Summary: The CAS extended Koopmans theorem (EKT) method is a special case of EKT, equivalent to the CI procedure involving all hole-state configurations derived from the active space of the reference wavefunction. The first ionization energy predicted by the EKT is not exact, but can approach the full CI result with arbitrary precision.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Yoshio Nishimoto
Summary: In multi-reference perturbation theory, the computational cost of analytic derivatives is strongly influenced by the size of the active space used in the reference self-consistent field calculation. By developing and implementing analytic gradients for restricted active space second-order perturbation theory (RASPT2) and complete active space second-order perturbation theory (CASPT2), previous limitations on active space size have been overcome, allowing for geometry optimizations with larger active spaces.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Amiel S. P. Paz, William J. J. Glover
Summary: We propose an efficient method to calculate property-based diabatic states and couplings using Lagrangian formalism. The method has a computational scaling independent of the number of adiabatic states used. It can be applied to other diabatization schemes and electronic structure methods as long as analytical energy gradients and integral derivatives with the property operator are available. We demonstrate the method on the calculation of Boys diabatic states obtained from state-averaged complete active space self-consistent field electronic structure calculations with GPU acceleration in the TeraChem package, and apply it to test the Condon approximation for hole transfer in a solvated model DNA oligomer.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Computer Science, Interdisciplinary Applications
Hwisang Jo, Kyungeun Lee, Mingyu Lee, Yongsu Jung, Ikjin Lee
Summary: This study proposed deriving analytical gradients of marginal and joint likelihood functions to calibrate both linear and nonlinear responses, without making any assumptions. The research showed that accurately calibrated output responses can be obtained by finding a better optimum in OBMC through the proposed method.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2021)
Article
Chemistry, Medicinal
Daniel Sethio, Vasanthanathan Poongavanam, Ruisheng Xiong, Mohit Tyagi, Duc Duy Vo, Roland Lindh, Jan Kihlberg
Summary: Conformational analysis is crucial for the design of bioactive molecules, and it becomes even more challenging for macrocycles due to their unique characteristics. In this study, we simulated the conformations of five designed macrocycles and verified the results against experimental measurements. Our simulations accurately predicted the intramolecular interactions and revealed a solvent-induced conformational switch of the macrocyclic ring. This provides a foundation for the rational design of molecular chameleons that can adapt to different environments.
JOURNAL OF CHEMICAL INFORMATION AND MODELING
(2023)
Article
Chemistry, Physical
Benedicte Sverdrup Ofstad, Hakon Emil Kristiansen, Einar Aurbakken, Oyvind Sigmundson Schoyen, Simen Kvaal, Thomas Bondo Pedersen
Summary: Real-time simulations of laser-driven electron dynamics allow for the extraction of molecular optical properties through all orders in response theory. However, accuracy deteriorates for higher-order responses due to nonadiabatic effects caused by the finite-time ramping of the external laser field. Three different approaches for extracting electrical properties from real-time electronic-structure simulations are investigated. Quadratic ramping is found to yield highly accurate results at approximately half the computational cost for polarizabilities, hyperpolarizabilities, and a measure of reliability.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Ignacio Fdez Galvan, Roland Lindh
Summary: In this study, a pseudodiabatic surrogate model is developed based on Gaussian process regression, which accurately reproduces the adiabatic surfaces and significantly reduces the computational effort required to obtain minimum energy crossing points using the restricted variance optimization method.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Andy Kaiser, Razan E. Daoud, Francesco Aquilante, Oliver Kuhn, Luca De Vico, Sergey I. Bokarev
Summary: We implemented the Frenkel exciton model into the OpenMolcas program package to calculate collective electronic excited states of molecular aggregates. Our protocol does not rely on diabatization schemes or supermolecule calculations, and the use of Cholesky decomposition for pair interactions improves computational efficiency. We applied our method to two test systems and compared it with the dipole approximation.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Giovanni Li Manni, Ignacio Fdez. Galvan, Ali Alavi, Flavia Aleotti, Francesco Aquilante, Jochen Autschbach, Davide Avagliano, Alberto Baiardi, Jie J. Bao, Stefano Battaglia, Letitia Birnoschi, Alejandro Blanco-Gonzalez, Sergey I. Bokarev, Ria Broer, Roberto Cacciari, Paul B. Calio, Rebecca K. Carlson, Rafael Carvalho Couto, Luis Cerdan, Liviu F. Chibotaru, Nicholas F. Chilton, Jonathan Richard Church, Irene Conti, Sonia Coriani, Juliana Cuellar-Zuquin, Razan E. Daoud, Nike Dattani, Piero Decleva, Coen de Graaf, Mickael G. Delcey, Luca De Vico, Werner Dobrautz, Sijia S. Dong, Rulin Feng, Nicolas Ferre, Michael Filatov (Gulak), Laura Gagliardi, Marco Garavelli, Leticia Gonzalez, Yafu Guan, Meiyuan Guo, Matthew R. Hennefarth, Matthew R. Hermes, Chad E. Hoyer, Miquel Huix-Rotllant, Vishal Kumar Jaiswal, Andy Kaiser, Danil S. Kaliakin, Marjan Khamesian, Daniel S. King, Vladislav Kochetov, Marek Krosnicki, Arpit Arun Kumaar, Ernst D. Larsson, Susi Lehtola, Marie-Bernadette Lepetit, Hans Lischka, Pablo Lopez Rios, Marcus Lundberg, Dongxia Ma, Sebastian Mai, Philipp Marquetand, Isabella C. D. Merritt, Francesco Montorsi, Maximilian Morchen, Artur Nenov, Vu Ha Anh Nguyen, Yoshio Nishimoto, Meagan S. Oakley, Massimo Olivucci, Markus Oppel, Daniele Padula, Riddhish Pandharkar, Quan Manh Phung, Felix Plasser, Gerardo Raggi, Elisa Rebolini, Markus Reiher, Ivan Rivalta, Daniel Roca-Sanjuan, Thies Romig, Arta Anushirwan Safari, Aitor Sanchez-Mansilla, Andrew M. Sand, Igor Schapiro, Thais R. Scott, Javier Segarra-Marti, Francesco Segatta, Dumitru-Claudiu Sergentu, Prachi Sharma, Ron Shepard, Yinan Shu, Jakob K. Staab, Tjerk P. Straatsma, Lasse Kragh Sorensen, Bruno Nunes Cabral Tenorio, Donald G. Truhlar, Liviu Ungur, Morgane Vacher, Valera Veryazov, Torben Arne Voss, Oskar Weser, Dihua Wu, Xuchun Yang, David Yarkony, Chen Zhou, J. Patrick Zobel, Roland Lindh
Summary: This article describes the developments of the open-source OpenMolcas chemistry software environment since spring 2020, focusing on the novel functionalities in the stable branch and interfaces with other packages. These developments cover a wide range of topics in computational chemistry and provide an overview of the chemical phenomena and processes that OpenMolcas can address.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Review
Chemistry, Multidisciplinary
Mickael G. Delcey
Summary: MultiPsi is an open-source MCSCF program that calculates ground and excited states properties of strongly correlated systems. It is written in Python/C++ and is highly modular, making it suitable for development and teaching. The code is also efficient and designed for modern high-performance computing environments.
WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE
(2023)
Review
Chemistry, Multidisciplinary
Benedicte Sverdrup Ofstad, Einar Aurbakken, Oyvind Sigmundson Schoyen, Hakon Emil Kristiansen, Simen Kvaal, Thomas Bondo Pedersen
Summary: In recent years, there has been growing interest in time-dependent coupled-cluster (TDCC) theory for simulating laser-driven electronic dynamics in atoms and molecules, as well as molecular vibrational dynamics. This review covers different types of single-reference TDCC theory based on orthonormal static, orthonormal time-dependent, or biorthonormal time-dependent spin orbitals. The time-dependent extension of equation-of-motion coupled-cluster theory and various applications of TDCC methods are also discussed, including the calculation of linear absorption spectra, response functions, high harmonic generation spectra, and ionization dynamics. Additionally, the role of TDCC theory in finite-temperature many-body quantum mechanics and other application areas is briefly described.
WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE
(2023)
Article
Chemistry, Physical
Juliana Cuellar-Zuquin, Ana Julieta Pepino, Ignacio Fdez Galvan, Ivan Rivalta, Francesco Aquilante, Marco Garavelli, Roland Lindh, Javier Segarra-Marti
Summary: We characterized the photochemically relevant conical intersections between different DNA/RNA nucleobases using CASSCF algorithms. Our results show that the size of the active space significantly affects the conical intersection topographies, while the basis set size seems to have a minor effect. We ruled out structural changes as a key factor and highlighted the importance of accurately describing the electronic states involved in these intersections.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Mikael Scott, Mickael G. G. Delcey
Summary: This article presents novel developments for the efficient evaluation of complex linear response functions of a multiconfigurational self-consistent field (MCSCF) wave function. The direct evaluation of linear response properties using the complex polarization propagator (CPP) approach is implemented within both the Tamm-Dancoff approximation (TDA) and the random phase approximation (RPA). The code's performance is illustrated with numerical examples, demonstrating its capability to handle large-scale MC-CPP calculations as well as the effect of including or excluding core orbitals in X-ray spectroscopy for small covalent metal complexes.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Eirill Hauge, Hakon Emil Kristiansen, Lukas Konecny, Marius Kadek, Michal Repisky, Thomas Bondo Pedersen
Summary: We propose a novel function fitting method for approximating the propagation of the time-dependent electric dipole moment from real-time electronic structure calculations. The method achieves arbitrary spectral resolution through extrapolation by fitting shorter dipole trajectories. Numerical testing demonstrates that this fitting method can reproduce high-resolution spectra using short dipole trajectories.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Gabriel L. S. Rodrigues, Mikael Scott, Mickael G. Delcey
Summary: Multiconfigurational pair-density functional theory (MC-PDFT) is an inexpensive way to describe both strong and dynamic correlations. This study demonstrates that the previously neglected imaginary component is actually necessary to reproduce the correct physical behavior, especially in low-spin open shell systems.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Multidisciplinary
Hannes Kneiding, Ruslan Lukin, Lucas Lang, Simen Reine, Thomas Bondo Pedersen, Riccardo De Bin, David Balcells
Summary: This paper introduces a method for studying transition metal complexes (TMCs) using deep graph learning, which utilizes electronic structure data from natural bond orbital (NBO) analysis and develops a representation called natural quantum graph (NatQG). With this method, the quantum properties of TMCs can be predicted, and the performance is better compared to traditional descriptor-based methods.
Article
Chemistry, Physical
Giovanni Li Manni, Ignacio Fdez. Galvan, Ali Alavi, Flavia Aleotti, Francesco Aquilante, Jochen Autschbach, Davide Avagliano, Alberto Baiardi, Jie J. Bao, Stefano Battaglia, Letitia Birnoschi, Alejandro Blanco-Gonzalez, Sergey I. Bokarev, Ria Broer, Roberto Cacciari, Paul B. Calio, Rebecca K. Carlson, Rafael Carvalho Couto, Luis Cerdan, Liviu F. Chibotaru, Nicholas F. Chilton, Jonathan Richard Church, Irene Conti, Sonia Coriani, Juliana Cuellar-Zuquin, Razan E. Daoud, Nike Dattani, Piero Decleva, Coen de Graaf, Mickael G. Delcey, Luca De Vico, Werner Dobrautz, Sijia S. Dong, Rulin Feng, Nicolas Ferre, Michael Filatov(Gulak), Laura Gagliardi, Marco Garavelli, Leticia Gonzalez, Yafu Guan, Meiyuan Guo, Matthew R. Hennefarth, Matthew R. Hermes, Chad E. Hoyer, Miquel Huix-Rotllant, Vishal Kumar Jaiswal, Andy Kaiser, Danil S. Kaliakin, Marjan Khamesian, Daniel S. King, Vladislav Kochetov, Marek Krosnicki, Arpit Arun Kumaar, Ernst D. Larsson, Susi Lehtola, Marie-Bernadette Lepetit, Hans Lischka, Pablo Lopez Rios, Marcus Lundberg, Dongxia Ma, Sebastian Mai, Philipp Marquetand, Isabella C. D. Merritt, Francesco Montorsi, Maximilian Morchen, Artur Nenov, Vu Ha Anh Nguyen, Yoshio Nishimoto, Meagan S. Oakley, Massimo Olivucci, Markus Oppel, Daniele Padula, Riddhish Pandharkar, Quan Manh Phung, Felix Plasser, Gerardo Raggi, Elisa Rebolini, Markus Reiher, Ivan Rivalta, Daniel Roca-Sanjuan, Thies Romig, Arta Anushirwan Safari, Aitor Sanchez-Mansilla, Andrew M. Sand, Igor Schapiro, Thais R. Scott, Javier Segarra-Marti, Francesco Segatta, Dumitru-Claudiu Sergentu, Prachi Sharma, Ron Shepard, Yinan Shu, Jakob K. Staab, Tjerk P. Straatsma, Lasse Kragh Sorensen, Bruno Nunes Cabral Tenorio, Donald G. Truhlar, Liviu Ungur, Morgane Vacher, Valera Veryazov, Torben Arne Voss, Oskar Weser, Dihua Wu, Xuchun Yang, David Yarkony, Chen Zhou, J. Patrick Zobel, Roland Lindh
Summary: This article describes the recent developments in the open-source chemistry software environment, OpenMolcas, since spring 2020. It focuses on the new functionalities and interfaces with other packages. The article presents various topics in computational chemistry, including electronic structure theory, electronic spectroscopy simulations, molecular structure optimizations, ab initio molecular dynamics, and other new features. Overall, it highlights the capabilities of OpenMolcas in addressing chemical phenomena and processes, making it an attractive platform for advanced atomistic computer simulations.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)