Article
Chemistry, Physical
Jeremy O. Richardson
Summary: In recent years, machine learning has been successful in simulating molecules in their ground electronic state through fitting ab initio potential-energy surfaces. However, to extend this to excited-state dynamics, nonadiabatic coupling vectors (NACs) must also be learned. Learning NACs in systems with conical intersections is challenging due to their double-valued nature. This study presents a machine learning approach that reconstructs NACs from a set of auxiliary single-valued functions.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Deping Hu, Yu Xie, Jiawei Peng, Zhenggang Lan
Summary: The study implements the symmetrical quasi-classical dynamics method based on the Meyer-Miller mapping Hamiltonian to investigate nonadiabatic dynamics at conical intersections of polyatomic systems, utilizing different approaches for zero-point energy correction of electronic mapping variables. Results show that the gamma-adjusted version of SQC/MM dynamics performs better in certain situations, demonstrating its effectiveness in simulating photoinduced dynamics of polyatomic systems.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Multidisciplinary
David B. Lingerfelt, Tao Yu, Anthony Yoshimura, Panchapakesan Ganesh, Jacek Jakowski, Bobby G. Sumpter
Summary: In this study, excited-state electronic structure calculations were used to investigate the diffusion pathway of silicon in graphene. It was found that the excited-state silicon diffusion pathway has a lower diffusion barrier than the ground-state pathway. Beam-induced transition rates indicate that the excited-state pathway can be accessed through irradiation of the defect site. Even in the limit of fully elastic scattering, upward nonadiabatic transitions are possible, increasing the diffusion barrier.
Article
Chemistry, Multidisciplinary
Wei Fang, Eric R. Heller, Jeremy O. Richardson
Summary: This article introduces a new semiclassical transition-state theory based on instanton theory to describe nonadiabatic tunnelling through conical intersections. The method is applied to electron transfer reactions and reveals the competition between heavy-atom tunnelling and geometric-phase effects.
Article
Chemistry, Multidisciplinary
Wei Fang, Eric R. Heller, Jeremy O. Richardson
Summary: Thermally activated chemical reactions involve overcoming potential-energy barriers, but standard rate theories fail in the presence of a conical intersection (CI). This is because CIs involve nonadiabatic processes that invalidate the Born-Oppenheimer approximation. Our study introduces novel semiclassical transition-state theories that incorporate nonadiabatic tunnelling through CIs, providing an intuitive understanding of the reaction mechanism. Using first-principles electronic-structure calculations, we demonstrate the importance of both heavy-atom tunnelling and geometric-phase effects in charge-transfer reactions involving CIs.
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
Chemistry, Physical
Shriya Gumber, Oleg V. Prezhdo
Summary: Decoherence is important in nonadiabatic molecular dynamics simulations as it can induce trajectory hopping and affect transition rates. It generally slows down quantum transitions, but in some cases, systems operate in the anti-Zeno regime where transitions are accelerated with faster decoherence. Therefore, it is crucial for NA-MD methods to describe both Zeno and anti-Zeno effects.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Marius S. Frank, Tsung-Han Lee, Gargee Bhattacharyya, Pak Ki Henry Tsang, Victor L. Quito, Vladimir Dobrosavljevic, Ove Christiansen, Nicola Lanata
Summary: The study demonstrates that in certain cases, the standard Gutzwiller approximation can be orders of magnitude off. This discrepancy is attributed to the method's inability to describe both Mott physics and the hybridization between correlated and itinerant degrees of freedom simultaneously. On the other hand, the ghost Gutzwiller approximation provides results in remarkable agreement with dynamical mean-field theory throughout the entire phase diagram.
Article
Materials Science, Multidisciplinary
B. Zwartsenberg, R. P. Day, E. Razzoli, M. Michiardi, M. X. Na, G. Zhang, J. D. Denlinger, I Vobornik, C. Bigi, B. J. Kim, I. S. Elfimov, E. Pavarini, A. Damascelli
Summary: In this study, the low-energy electronic structure of Sr2IrO4 was investigated using experimental observation and theoretical calculations. It was found that a simple pseudospin-12 model fails to fully capture the complexity of the system, and a realistic multiband Hubbard model is needed to describe the interplay between spin-orbital entanglement and electron-electron interactions. The results have implications for understanding multiorbital materials with closely spaced energy scales.
Review
Chemistry, Multidisciplinary
Samuele Giannini, Jochen Blumberger
Summary: Organic semiconductors have enabled disruptive technologies in this century, but the nature of charge transport in these materials has puzzled scientists for many years. Recent progress in theory and simulation has led to a unified understanding, and this paper reviews a tool called direct charge carrier propagation by quantum-classical nonadiabatic molecular dynamics. The simulations show that charge carriers in these materials can either localize or delocalize depending on various factors, and predict the formation of flickering polarons that expand and propagate through the material.
ACCOUNTS OF CHEMICAL RESEARCH
(2022)
Article
Chemistry, Physical
Jie Peng, Xin He, Yao Li, Jianxin Guan, Baihua Wu, Xinmao Li, Zhihao Yu, Jian Liu, Junrong Zheng
Summary: Understanding the mechanisms of aggregation-induced emission (AIE) is crucial for the design of better AIE-gens. Diphenylethylene (DPE) featured molecules, with their propeller structure, are important AIE-gens. Through ultrafast UV/IR spectroscopy and theoretical calculations, three representative DPE-featured AIE-gens, triphenylethylene, cis-stilbene, and trans-stilbene, were investigated. The results suggest that crossing conical intersections (CIs) with flexible structural evolutions in solutions reduces fluorescence, while crossing CIs is restricted in solids, leading to no fast nonradiative decay competing with spontaneous emission.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Christopher E. Patrick
Summary: This article investigates the magnetocrystalline anisotropy (MCA) of MnBi alloy in the presence of magnetic disorder. The MCA and its dependence on magnetization angle and temperature are calculated using first-principles density-functional theory. The results show that the MCA decreases with increasing temperature and is influenced by the order parameter. In addition, a spin reorientation transition can be triggered by removing electrons.
Article
Materials Science, Multidisciplinary
Jean-Philippe Banon, Pierre Pelletier, Claude Weisbuch, Svitlana Mayboroda, Marcel Filoche
Summary: This study presents a mathematical and computational model that can simulate the optoelectronic response of semiconductor alloys at the nanoscale and account for quantum localization effects. The model is validated and then applied to calculate light absorption in 3D InGaN alloys, obtaining detailed structures of the absorption tail and Urbach energies. Additionally, the model allows for computing 3D maps of the effective locally absorbed power.
Article
Chemistry, Multidisciplinary
Yue-Rou Zhang, Dao-Fu Yuan, Lai-Sheng Wang
Summary: Although the adiabatic potential energy surfaces are crucial in understanding the electronic structure and spectroscopy of molecular systems, nonadiabatic effects due to electronic states coupling by nuclear motions are common in complex molecular systems. In this study, the complex vibronic levels of the triazolyl radical were completely unraveled using photodetachment spectroscopy and resonant photoelectron imaging. The experimental vibronic information obtained will be valuable in validating theoretical models for treating nonadiabatic effects involving multiple electronic states.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Seonghoon Choi, Jiri Vanicek
Summary: The study introduces a method to assess the potential errors introduced by neglecting residual couplings by comparing quantum dynamics simulations with or without these couplings. The results show that neglecting residual couplings can lead to inaccurate dynamics, while simulations with the exact quasidiabatic Hamiltonian always yield accurate results.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Camilo Zuluaga, Vincent A. Spata, Spiridoula Matsika
Summary: This study compares how 40 different quantum mechanical methods describe the excited states of a guanine-thymine pi-stacked nucleobase dimer system, including both the 5'-TG-3' and 5'-GT-3' conformations. The distance between the nucleobases is found to be a major factor in determining the energy of the CT state and the difference in dipole moments between the CT and ground state. Compared to states localized on one nucleobase, there is a wider range of values (and errors) for the energies of CT states.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Physical
Salsabil Abou-Hatab, Vincenzo Carnevale, Spiridoula Matsika
Summary: Modeling optical spectra of molecules in solution is challenging due to the need to accurately capture solvation effects. Mutual polarization is found to be crucial for reproducing absorption spectra, with fluorescence modeling being particularly challenging. Different solvation models have varying effects on electronic excited states, requiring re-evaluation of force field parameters for accurate fluorescence modeling.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Patricia Vindel-Zandbergen, Spiridoula Matsika, Neepa T. Maitra
Summary: A recently derived surface-hopping algorithm called SHXF has shown excellent performance in capturing nonadiabatic dynamics, especially when multiple occupied states are involved. By studying the vibronic coupling model of the uracil cation, the crucial role of the additional term introduced in SHXF is demonstrated, revealing that traditional surface-hopping methods fail to accurately predict dynamics through a three-state intersection.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Mushir Thodika, Spiridoula Matsika
Summary: This article discusses the formation of anion resonances in low-energy electron-induced reactions and proposes a new method for characterizing these resonances. By introducing a projected complex absorbing potential within the multireference configuration interaction framework, the authors are able to efficiently capture the mixing between different channels, showing significant consequences for the resonances' lifetimes.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Y. Sajeev, Mushir Thodika, Spiridoula Matsika
Summary: A simple and practical method for calculating the energy position and decay width of autoionization resonances is presented. This method combines the use of a real-valued continuum-remover potential and the Feshbach projection operator partitioning technique to obtain a unique partitioning of the total wave function. The CR-FPO formalism is simple to implement and has been demonstrated to be accurate in calculating resonance states.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Biochemistry & Molecular Biology
Vaibhav Singh, Hugo A. Lopez Pena, Jacob M. Shusterman, Patricia Vindel-Zandbergen, Katharine Moore Tibbetts, Spiridoula Matsika
Summary: The dynamics of DMMP radical cation after strong field adiabatic ionization has been studied using a combination of experimental and computational methods. The pump-probe experiments show coherent oscillations of the parent ion yield, while the yields of two fragments oscillate with a slight phase shift. The computational results and experimental observations reveal that DMMP exists in two conformations and exhibits different dissociation products when excited to higher electronic states.
Article
Biochemistry & Molecular Biology
Mohammed Sorour, Andrew H. Marcus, Spiridoula Matsika
Summary: In this study, different methods were used to simulate the absorption spectrum of Cy3 dye, finding that the adiabatic approximation of the Franck-Condon method is more suitable for modeling spectra with strong vibronic contributions, while ensemble methods are not. Thermal effects, low frequency modes, and simultaneous vibrational excitations were found to have prominent contributions to the Cy3 spectrum, with the solvent significantly stabilizing the energetics.
Article
Chemistry, Physical
Cate S. Anstoeter, Salsabil Abou-Hatab, Mushir Thodika, Spiridoula Matsika
Summary: The EFP approach is an effective method for including solvation effects in condensed phase properties and reactivity. This study examines the performance of the EFP method in describing microsolvation in electronically excited states. The results show minimal differences between QM/EFP and full quantum results when averaging over multiple configurations of microsolvated clusters, although individual configurations may have larger errors. Diffuse states have slightly larger errors, and QM/EFP may be less accurate in capturing state ordering changes. However, other properties such as photoelectron images and lifetimes are well described by the method.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Pratip Chakraborty, Yusong Liu, Samuel McClung, Thomas Weinacht, Spiridoula Matsika
Summary: Nonadiabatic excited state dynamics play a crucial role in various processes. The combination of theoretical and experimental developments has led to significant progress in this field, providing insights into the photophysical behavior of molecules. This Feature Article utilizes recent work combining time-resolved photoelectron spectroscopy with theoretical non-adiabatic dynamics to highlight important lessons learned. By comparing the nonadiabatic excited state dynamics of three different organic molecules, namely uracil, 1,3-cyclooctadiene, and 1,3-cyclohexadiene, the study aims to elucidate the relationship between structure and dynamics. The comparison emphasizes the influence of rigidity on dynamics and the challenges in accurately capturing dynamics through calculations.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Chuan Cheng, Vaibhav Singh, Spiridoula Matsika, Thomas Weinacht
Summary: In this study, we combine covariance velocity map imaging and trajectory surface hopping calculations to investigate the ionization yields of fragment ions from formaldehyde under strong field double ionization. By comparing the calculated kinetic energy release with experimental values based on momentum resolved covariance measurements, we determine the state resolved double ionization yields as a function of laser intensity and pulse duration down to 6 fs (two optical cycles).
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Cole R. Sagan, Cate S. Anstoeter, Mushir Thodika, Kenneth D. Wilson, Spiridoula Matsika, Etienne Garand
Summary: The properties of optically allowed electronic states of the tetracene radical anion have been studied using photodetachment yield spectroscopy, and the results have been compared with high-level electronic structure computations, showing that these calculations can accurately describe the energy and lifetime of anion resonances.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Wook Lee, Spiridoula Matsika
Summary: A cyclobutane pyrimidine dimer (CPD) is a photolesion that forms through a cycloaddition reaction between stacked pyrimidine bases upon UV light absorption. Flanking nucleotide sequences have been found to play a crucial role in CPD formation or self-repair, and understanding the mechanisms behind this sequence dependence is important for identifying vulnerable DNA sequences. This Perspective highlights the role of computational studies in investigating how flanking nucleotide sequences affect CPD formation or self-repair.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Chemistry, Physical
Samuel McClung, Dakshitha Abeygunewardane, Spiridoula Matsika, Thomas Weinacht
Summary: Time-resolved photoionization measurements were conducted on o-nitrophenol using UV laser pumping and VUV laser probing. The results were interpreted through electronic structure calculations, revealing the formation of a bicyclic intermediate and subsequent NO dissociation through internal conversion and intersystem crossing. The combination of photoelectron and photoion spectroscopy with computational results provided convincing evidence of intersystem crossing that is difficult to establish using a single technique.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Mohammed I. Sorour, Andrew H. Marcus, Spiridoula Matsika
Summary: This study simulates the vibronic spectrum of the Cy3 dye and explains the origin of the experimental signatures in its linear absorption spectrum. It finds that the spectral features are related to the energy of the excitonic state and the polarity of the solvent.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Vaibhav Singh, Chuan Cheng, Thomas Weinacht, Spiridoula Matsika
Summary: Combined theoretical and experimental work demonstrates the stability of the first excited state of the formaldehyde dication, which does not dissociate. This result is based on the examination of relaxation pathways and dissociation channels, and is confirmed by experimental analysis of the kinetic energy distribution.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)