Article
Chemistry, Multidisciplinary
Thomas Bondo Pedersen, Susi Lehtola, Ignacio Fdez Galvan, Roland Lindh
Summary: This review provides an overview of the RI/DF and CD methods in electronic structure calculations, highlighting the close relationship between these two approaches. It traces the evolution and current state of the CD method, which offers not only a numerical procedure for handling ERIs, but also highly accurate approaches for generating auxiliary basis sets for the RI/DF approximation.
WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE
(2023)
Article
Quantum Science & Technology
Mario Motta, Erika Ye, Jarrod R. McClean, Zhendong Li, Austin J. Minnich, Ryan Babbush, Garnet Kin-Lic Chan
Summary: The quantum simulation of quantum chemistry faces challenges due to the high gate complexity, but this research significantly reduces the gate complexity through low-rank factorization and term truncation. This allows for Trotter steps of electronic structure Hamiltonian with O(N-3) gate complexity in small simulations, improving to O(N-2) in the asymptotic regime. Additionally, unitary Coupled Cluster Trotter steps have O(N-3) gate complexity as basis size increases for a given molecule.
NPJ QUANTUM INFORMATION
(2021)
Article
Chemistry, Physical
Ugur Bozkaya
Summary: Efficient computation of molecular integrals and their derivatives is crucial in modern quantum chemistry for property evaluation. The Molint application programming interface (API) framework reported in this study provides a smooth approach to calculate these integrals and their first derivatives, including overlap, dipole, kinetic, potential, 2-index, and 3-index integrals. Molint is a C++/Fortran hybrid code, free software, and offers shared-memory parallel programming techniques for increased efficiency. Results demonstrate Molint as an efficient and user-friendly API for molecular integral computation.
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
(2021)
Article
Physics, Particles & Fields
Wen Chen
Summary: In this paper, the reduction of Feynman integrals in the parametric representation was discussed, where tensor integrals were directly parametrized using a generator method. The study involved constructing and solving parametric integration-by-parts (IBP) identities, and also deriving polynomial equations for the operators that generate tensor integrals. Two methods were developed to reduce tensor integrals, one involving introducing auxiliary parameters and the other using the technique of Grobner basis combined with symbolic rules.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Chemistry, Physical
Danjo De Chavez, Roland Lindh
Summary: This article introduces Cholesky decomposition and RI techniques as inner projection methods for efficiently evaluating two-electron integrals, and explains their close relationship and the improvement of accuracy through correcting one-centred two-electron integrals in the RI approach.
Article
Physics, Nuclear
Long-Bin Chen, Jian Wang
Summary: The analytic calculation of two-loop master integrals relevant for tW production at hadron colliders is presented in this work. By selecting a canonical basis, the differential equations for the master integrals are transformed into the d ln form. The analytical results, expressed in terms of multiple polylogarithms, have been verified through numerical computations.
Article
Astronomy & Astrophysics
Tyler A. Gordon, Eric Agol
Summary: We present a solution for light curve analysis of two bodies mutually transiting a star with polynomial limb darkening, including code implementation. The work primarily focuses on the detectability of exomoons, but it can also be applied to other systems.
ASTRONOMICAL JOURNAL
(2022)
Article
Chemistry, Physical
Goran Kovacevic
Summary: The Gaussian product rule for two-electron wave functions is introduced, providing a new method for solving two-electron integrals. The solution is obtained by expanding inverse inter-electron separation and integrating in spherical coordinates, resulting in four integrals that can be solved. It is demonstrated that this solution can deliver accurate results similar to the McMurchie-Davidson scheme.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Chinami Takashima, Hiromi Nakai
Summary: The Cholesky decomposition and lower-upper decomposition methods were utilized to handle the two-electron integral matrices in an infinite-order two-component relativistic Hamiltonian. CD was used to calculate the symmetric TEI matrices, such as Coulomb-like and specific spin-free interaction terms, while LUD was used for the asymmetric TEI matrix, namely the Darwin-like term. Unitary transformation was performed on the decomposed matrices. Numerical assessments suggest that the proposed method can reduce the computational cost without sacrificing accuracy.
CHEMICAL PHYSICS LETTERS
(2023)
Article
Mathematics, Applied
Manuel Duarte Ortigueira
Summary: This paper investigates two-sided derivatives, Riesz-Feller potentials, and their interrelations, introducing a general integral formulation for two-sided derivatives and anti-derivatives. It also explores cases of integer orders and proposes regularized Riesz-Feller derivatives.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2021)
Article
Mathematics, Applied
Antoni Ferragut, Armengol Gasull, Xiang Zhang
Summary: In this paper, we provide an upper bound for the number of functionally independent meromorphic first integrals that a discrete dynamical system generated by an analytic map f can have in a neighborhood of one of its fixed points. This bound is derived based on the resonances among the eigenvalues of the differential of f at this point, inspired by similar Poincare type results for ordinary differential equations. We also illustrate our findings with several examples, some of which are motivated by the study of difference equations.
JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS
(2023)
Article
Chemistry, Physical
Nobuki Inoue, Yoshihiro Watanabe, Haruyuki Nakano
Summary: The study derived and implemented two-electron repulsion operator formulas for the second- and third-order Douglas-Kroll (DK2 and DK3) method, and observed small energy differences compared to the four-component method. Additionally, approximation formulas for small component-type two-electron integrals were derived and accurately reproduced unapproximated values.
CHEMICAL PHYSICS LETTERS
(2021)
Article
Mathematics, Applied
Maliha Rashid, Amna Kalsoom, Maria Sager, Mustafa Inc, Dumitru Baleanu, Ali S. Alshomrani
Summary: This article examines the categories of fractional integrals and derivatives, classifying them into two main categories with and without general analytical kernels. It also explores the Mellin transform for fractional differential operators with general analytical kernels in both Riemann-Liouville and Caputo derivatives, as well as the relationship between Mellin transforms and Laplace and Fourier transforms.
Article
Nanoscience & Nanotechnology
S. Chaudhuri
Summary: The study analyzed the energy levels of two interacting electrons in a 2D quantum dot confined by a finite Gaussian potential and subjected to a uniform magnetic field, obtaining analytic results for the energy spectrum. The ground state transitions and energy as a function of magnetic field were calculated, compared with experimental data, and previous theoretical results.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Mathematics, Applied
Avram Sidi
Summary: In this study, we unified the treatment of HFP integrals and developed numerical quadrature formulas to improve the accuracy of computations. We also extended the convergence analysis to functions with certain analytic properties and proved error bounds for the numerical quadrature formulas.
Article
Chemistry, Physical
Hakon Emil Kristiansen, Benedicte Sverdrup Ofstad, Eirill Hauge, Einar Aurbakken, Oyvind Sigmundson Schoyen, Simen Kvaal, Thomas Bondo Pedersen
Summary: In this study, we derive real-time (RT) time and its biorthogonal companion from the time-dependent bivariational principle and a parametrization based on the exponential orbital rotation operator formulation. Applying the TDOMP2 method, we find that absorption spectra are of similar quality to TDCC2 spectra, while frequency-dependent polarizabilities and hyperpolarizabilities are significantly closer to TDCCSD results compared to TDCC2 simulations.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
L. Adamowicz, S. Kvaal, C. Lasser, T. B. Pedersen
Summary: This research demonstrates the emergence of alignment from non-BO quantum dynamics simulations and extracts the degree of alignment using pseudo-proton coordinates. The study utilizes time-independent explicitly correlated Gaussian basis functions and a variational, electric-field-dependent basis-set construction procedure.
JOURNAL OF CHEMICAL PHYSICS
(2022)
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
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
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, 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)
Article
Chemistry, Multidisciplinary
Scott Wilcox, Daniel Sethio, Jas S. Ward, Antonio Frontera, Roland Lindh, Kari Rissanen, Mate Erdelyi
Summary: The interaction between a [bis(pyridine)iodine(i)](+) cation and a [bis(pyridine)silver(i)](+) cation, where an iodonium ion acts as a nucleophile by transferring electron density to the silver(i) cation, is reinvestigated in this study. No measurable interaction is observed between the cationic species in solution using NMR. DFT calculations suggest that any attractive interaction between these complexes in solution is primarily due to the pi-pi interaction of pyridines.
CHEMICAL COMMUNICATIONS
(2022)