Article
Physics, Condensed Matter
John McFarland, Efstratios Manousakis
Summary: Imaginary-time time-dependent density functional theory (it-TDDFT) is proposed as an alternative method for obtaining the ground state within density functional theory, avoiding convergence difficulties encountered by the self-consistent-field iterative method. By modifying the Quantum ESPRESSO package, it-TDDFT propagation for periodic systems has been successfully implemented, demonstrating accurate results for different calculations using ultra-soft or norm-conserving pseudo potentials.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Chemistry, Physical
Jared R. Williams, Nicolas Tancogne-Dejean, Carsten A. Ullrich
Summary: Time-dependent density-functional theory (TDDFT) is an efficient method for calculating optical spectra, providing insight into exciton dynamics by obtaining exciton wave functions and understanding the formation and dissociation of excitons in real time.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Physical
Yevhen Horbatenko, Saima Sadiq, Seunghoon Lee, Michael Filatov, Cheol Ho Choi
Summary: The MRSF-TDDFT method demonstrates high accuracy in describing the multiconfigurational electronic states of diradicals and diradicaloids, avoiding spin-contamination pitfalls. It accurately predicts adiabatic singlet-triplet gaps and various effects in different systems.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Multidisciplinary
Paul Geerlings, Frank De Proft
Summary: The necessity of incorporating new external variables in the context of conceptual DFT (CDFT) is discussed. Electric and magnetic fields, mechanical forces, and confinement are proposed as valuable new variables. The study shows that these new variables are important for understanding chemical phenomena under different conditions.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2023)
Article
Physics, Condensed Matter
Alexander J. White, Lee A. Collins, Katarina Nichols, S. X. Hu
Summary: Warm dense matter (WDM) is an intermediate phase between condensed matter and classical plasmas. Understanding the energy loss of high energy ions in WDM is important for inertial confinement fusion research. However, electron coupling, degeneracy, and quantum effects make accurate calculation of stopping power difficult.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Chemistry, Physical
Meilani Wibowo, Tom J. P. Irons, Andrew M. Teale
Summary: This study presents the implementation of real-time time-dependent Hartree-Fock and current density functional theory for molecules in strong magnetic fields, allowing for the investigation of electronic absorption spectra and their dependence on field strength and orientation. The performance of various propagator algorithms for real-time methods is evaluated and molecular orbital pair decomposition analysis is used to provide insights into electronic transitions and spectra evolution in strong magnetic fields.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Quantum Science & Technology
Luigi Ranalli, Carla Verdi, Lorenzo Monacelli, Georg Kresse, Matteo Calandra, Cesare Franchini
Summary: This study combines density functional theory calculations with a machine-learned force field method to investigate the quantum paraelectric state in the quantum ferroelectric material KTaO3. The results demonstrate the importance of including anharmonic terms to stabilize the spurious imaginary ferroelectric phonon predicted by DFT in the harmonic approximation, in agreement with experiments. This work proposes a robust computational workflow capable of accounting for collective behaviors involving different degrees of freedom and occurring at large time/length scales, paving the way for precise modeling and control of quantum effects in materials.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Computer Science, Interdisciplinary Applications
Dong An, Di Fang, Lin Lin
Summary: Direct simulation of general quantum states using the von Neumann dynamics is expensive. By generalizing the parallel transport dynamics to general quantum states, we propose an improved method that enhances simulation efficiency and time step size.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Physics, Multidisciplinary
Shohreh Janjan, Fardin Kheirandish
Summary: In this paper, the quantum propagator for a general time-dependent quadratic Hamiltonian is derived by considering the properties of the propagator and the fulfillment of two independent partial differential equations by the quantum propagator. As an application, the quantum propagator for a linear chain of interacting oscillators is obtained for both periodic and Dirichlet boundary conditions. The propagation of state and excitation along the chain is studied in the absence and presence of an external classical source, revealing a constant speed of excitation propagation along the chain as indicated by the straight line trajectory of the first maxima of the probability amplitude P(n, tau) in the (n, tau)-plane.
Article
Nanoscience & Nanotechnology
Mohamed A. Abdelati, Mohamed M. Fadlallah, Yosr E. E-D Gamal, Ahmed A. Maarouf
Summary: This study investigated the structural stabilities and optical properties of graphene quantum dots (GQDs) and holey GQDs with different sizes, edge terminations, and pore passivations using density functional theory (DFT) and time dependent DFT. Results showed that the optical spectra of GQDs primarily depend on their size, while pore passivation has the biggest effect on the absorption spectra of holey GQDs. These findings can be applied in the development of promising materials for various applications, such as biological sensors and optoelectronic devices.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2021)
Article
Physics, Mathematical
Juan J. Omiste, Rosario Gonzalez-Ferez, Rafael Ortega
Summary: In this study, the interaction between a linear molecule with azimuthal symmetry and external fields is investigated. By analyzing the behavior of closed orbits, a semi-theoretical method is developed to detect classical monodromy, and its effectiveness is numerically demonstrated.
JOURNAL OF MATHEMATICAL PHYSICS
(2022)
Article
Chemistry, Physical
Meilani Wibowo-Teale, Benjamin J. Ennifer, Andrew M. Wibowo-Teale
Summary: The first finite basis set implementation of the real-time time-dependent self-consistent field method in a dynamic magnetic field using London atomic orbitals is presented. The accuracy of this approach is benchmarked against numerical results, and it is found that a relatively small compact basis set is sufficient. The study demonstrates the utility of this method for extreme dynamic magnetic fields, providing a stress-test on basis choice.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Fluids & Plasmas
Manuel Weber, James K. Freericks
Summary: We propose an exact Monte Carlo method for simulating the nonequilibrium dynamics of electron-phonon models with zero phonon frequency in the adiabatic limit. Our approach efficiently evolves the electronic subsystem in a time-dependent electromagnetic field for each phonon configuration by sampling the equilibrium phonon distribution. We demonstrate the usefulness of our method in studying charge-density-wave systems under pulsed electric fields, as observed in pump-probe experiments.
Review
Chemistry, Physical
Neepa T. Maitra
Summary: Time-dependent density functional theory is a preferred method for calculating spectra and response properties in physics, chemistry, and biology. Its ability to scale to larger systems has made computations possible that were not previously achievable. While simple functional approximations have been successful in handling increasingly complex and interesting systems, there is a growing awareness that these approximations may fail for certain classes of problems. This review discusses the challenges and progress in describing double excitations and charge-transfer excitations, two common obstacles to the theory's application.
ANNUAL REVIEW OF PHYSICAL CHEMISTRY
(2022)
Article
Astronomy & Astrophysics
Matthias Diez, Reinhard Alkofer, Christian Kohlfuerst
Summary: Particle production by ultra-strong electric fields is a well-studied research field, but the formation time of a particle remains mysterious. In this study, we provide an interpretation of a particle distribution at finite times and identify the relevant time scales for particle formation in quantum physics within and beyond perturbation theory.
Article
Chemistry, Physical
Lea M. Ibele, Yorick Lassmann, Todd J. Martinez, Basile F. E. Curchod
Summary: The AIMS method simulates excited-state dynamics of molecular systems using TBFs, with the SSAIMS strategy aiming to limit TBFs and reduce computational cost while maintaining accuracy. Testing on three molecules showed that SSAIMS can accurately reproduce AIMS results at a lower cost, with the best results achieved through a stochastic-selection process based on overlap criteria.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Darya Shchepanovska, Robin J. Shannon, Basile F. E. Curchod, David R. Glowacki
Summary: In this study, an extension of the energy-grained master equation (EGME) was proposed and tested for handling nonadiabatic hopping, enabling modeling of competition between collisional relaxation and population transfer processes. The performance evaluation showed that the EGME approach can capture important aspects of dynamics, including kinetic timescales and diabatic trapping.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Computer Science, Interdisciplinary Applications
Thomas W. Keal, Alin-Marin Elena, Alexey A. Sokol, Karen Stoneham, Matt I. J. Probert, Clotilde S. Cucinotta, David J. Willock, Andrew J. Logsdail, Andrea Zen, Phil J. Hasnip, Ian J. Bush, Matthew Watkins, Dario Alfe, Chris-Kriton Skylaris, Basile F. E. Curchod, Qiong Cai, Scott M. Woodley
Summary: The transition to exascale computing enables simulations of unprecedented accuracy and complexity. The focus is on materials and molecular modeling that aim for high fidelity in silico experiments on technologically interesting complex systems. This progress presents significant challenges to software, particularly in exploiting parallelism and effectively managing workflows and data on such platforms.
COMPUTING IN SCIENCE & ENGINEERING
(2022)
Article
Chemistry, Physical
Lea M. Ibele, Basile F. E. Curchod, Federica Agostini
Summary: In this work, a comparison is made between the Born-Oppenheimer picture and the exact factorization in analyzing a full in silico photochemical experiment. The exact factorization offers an alternative understanding of photochemistry that does not rely on traditional concepts.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Cate S. Anstoter, Basile F. E. Curchod, Jan R. R. Verlet
Summary: This passage discusses the structural changes in chromophores of photoactive proteins that initiate biological responses, with an ultrafast relaxation of the molecular framework occurring before isomerization. Using time-resolved photoelectron imaging, the motion of an isolated model chromophore is captured, showing a spectral shift and change in photoelectron anisotropy. Electronic structure calculations allow for quantitative assignment of the geometric and electronic structure changes to a planar intermediate, facilitating the subsequent primary step.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
Connor J. Clarke, Jemma A. Gibbard, Lewis Hutton, Jan R. R. Verlet, Basile F. E. Curchod
Summary: This study presents a detailed investigation of the photochemistry of isolated pyruvate anions. It reveals that the photoexcitation of pyruvate anions by UVA light leads to the formation of CO2, CO, and CH3-, which may have significant consequences for atmospheric chemistry.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Andrew T. Turley, Promeet K. Saha, Andrew Danos, Aisha N. Bismillah, Andrew P. Monkman, Dmitry S. Yufit, Basile F. E. Curchod, Marc K. Etherington, Paul R. McGonigal
Summary: This study investigates the relationship between solid-state luminescence and photocyclization of oligoaryl alkene chromophores by modulating the conjugation length. It is found that the emission of heptaaryl cycloheptatriene is turned off upon breaking the conjugation, but extended polycyclic frameworks can be formed. This method can be used to manipulate emission properties and selectively cyclize aromatic compounds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Multidisciplinary Sciences
Federica Agostini, Basile F. E. Curchod
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2022)
Article
Chemistry, Physical
Emanuele Marsili, Antonio Prlj, Basile F. E. Curchod
Summary: Due to the unstable and short-lived nature of organic molecules, it is challenging to experimentally characterize the photochemical reactions triggered by sunlight absorption in the troposphere. In this study, a computational protocol is used to predict the photochemical fate of 2-hydroperoxypropanal (2-HPP) in the actinic region, leveraging different electronic structure methods and trajectory surface hopping to understand the mechanistic details of nonradiative processes.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Lewis Hutton, Basile F. E. Curchod
Summary: The photochemistry of pyruvic acid has attracted significant attention due to its relevance to atmospheric chemistry. In this study, a combination of excited- and ground-state ab initio molecular dynamics was used to explore the possible mechanisms leading to the decarboxylation of pyruvic acid. The calculations revealed the importance of a proton-coupled electron transfer mechanism in the first excited electronic state, triggering a nonadiabatic transfer to the ground electronic state.
Article
Chemistry, Physical
Yorick Lassmann, Daniel Hollas, Basile F. E. Curchod
Summary: AIMS describes nonadiabatic dynamics by expanding nuclear wave functions in a basis of traveling multidimensional Gaussians, but the growth of TBFs can impact computational efficiency. AIMSWISS, a modified version, dramatically reduces the number of TBFs.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Multidisciplinary
Jiri Janos, Ivo S. Vinklarek, Jozef Rakovsky, Deb Pratim Mukhopadhyay, Basile F. E. Curchod, Michal Farnik, Petr Slavicek
Summary: In this study, the influence of photon energy on the photochemistry of CF3COCl molecule was investigated using nonadiabatic ab initio molecular dynamics techniques and velocity map imaging experiment. The results reveal that selective release of CO and Cl can be achieved by controlling the excitation wavelength.
ACS EARTH AND SPACE CHEMISTRY
(2023)
Article
Chemistry, Physical
Jack T. Taylor, David J. Tozer, Basile F. E. Curchod
Summary: Conical intersections are fundamental to understanding ultrafast, nonadiabatic processes in photochemistry. However, accurately calculating potential energy surfaces near conical intersections remains a challenge for popular electronic structure methods. This study focuses on conical intersections between excited electronic states and evaluates the performance of different methods in describing their topology and topography.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Anastasia Klimash, Antonio Prlj, Dmitry S. Yufit, Abhijit Mallick, Basile F. E. Curchod, Paul R. McGonigal, Peter J. Skabara, Marc K. Etherington
Summary: Control of delayed emission of organic compounds is crucial for new display technology development and the utilization of organic emitters in sensing and fluorescence microscopy. This study demonstrates that delayed fluorescence can be activated in room-temperature phosphorescence emitters by quaternizing the sp(2)-hybridized heterocyclic nitrogens. Furthermore, strategic positioning of a carbazole donor allows for tuning the origins of delayed fluorescence from triplet-triplet annihilation to thermally activated delayed fluorescence, uncovering the intersection between phosphorescence and delayed fluorescence.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Lei Ji, Stefan Riese, Alexander Schmiedel, Marco Holzapfel, Maximillian Fest, Joern Nitsch, Basile F. E. Curchod, Alexandra Friedrich, Lin Wu, Hamad H. Al Mamari, Sebastian Hammer, Jens Pflaum, Mark A. Fox, David J. Tozer, Maik Finze, Christoph Lambert, Todd B. Marder
Summary: Reversible conversion between excited states is crucial in various photophysical phenomena. By conducting experiments and calculations, we discovered that the energy gaps and barriers among the locally-excited and charge-transfer states in 1-(pyren-2'-yl)-o-carborane are negligible, making all three states accessible at room temperature. Furthermore, the internal-conversion and reverse internal-conversion processes occur much faster than radiative decay, resulting in the same lifetimes and thermodynamic equilibrium of the two states.
