Article
Chemistry, Physical
Yanzhao Lu, Minggang Guo, Zhifan Wang, Fan Wang
Summary: The electronic structure of Tl2 and Nh2 molecules exhibits significant multireference character, with spin-orbit coupling playing a crucial role in their properties. The use of single-reference EOM-CCSD and multi-reference IHFSCCSD methods helps in investigating their low-lying states.
CHEMICAL PHYSICS LETTERS
(2021)
Article
Chemistry, Physical
Bernhard Kretz, David A. Egger
Summary: In this study, it is suggested that using time-dependent density functional theory with optimally tuned range-separated hybrid functionals can accurately obtain excited-state molecular geometries, particularly in cases involving complex excited-state potential energy surfaces with local and charge-transfer excitations.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Inorganic & Nuclear
Luca Babetto, Silvia Carlotto, Alice Carlotto, Marzio Rancan, Gregorio Bottaro, Lidia Armelao, Maurizio Casarin
Summary: This study proposes a theoretical protocol that combines DFT and CAS calculations for Eu3+ complexes, emphasizing the importance of spin multiplicity and the number of states in energy calculations. The protocol enables a rigorous, full ab initio treatment of Eu3+ complexes and can be extended to other Ln(3+) ions.
INORGANIC CHEMISTRY
(2021)
Article
Chemistry, Physical
Sasha C. North, Nuno M. S. Almeida, Timothe R. L. Melin, Angela K. Wilson
Summary: In this study, CASSCF and MRCI+Q calculations were performed for LrF and LrO molecules, revealing 19 and 20 electronic states, respectively. Multiple dissociation channels were considered for both molecules, and various properties such as bond lengths, vibrational frequencies, anharmonicity constants, and excitation energies were calculated for the first time. Bond dissociation energies were also calculated using different levels of theory.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Ilia M. Mazin, Alexander Yu Sokolov
Summary: This study presents a new implementation and benchmark of approximations in multireference algebraic diagrammatic construction theory for simulations of neutral electronic excitations and UV/vis spectra of strongly correlated molecular systems. The results demonstrate that the proposed MR-ADC methods outperform third-order single-reference ADC approximation for weakly correlated electronic states and are competitive with equation-of-motion coupled cluster theory results. For states with multireference character, the performance of the MR-ADC methods is similar to that of N-electron valence perturbation theory.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Multidisciplinary
Anders Hutcheson, Alexander Christian Paul, Rolf H. Myhre, Henrik Koch, Ida-Marie Hoyvik
Summary: Coupled cluster models are effective in describing ground and excited state potential energy surfaces of photoswitchable systems, especially when triple excitations are included. Molecular geometry and basis set significantly impact the vertical excitation energies for the lowest excited states. Efficient implementations of coupled cluster models can provide valuable information for preliminary studies of photoswitchable systems before more complex dynamics approaches are pursued.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2021)
Article
Chemistry, Physical
Gabriel Greene-Diniz, David Munoz Ramo
Summary: The VQE algorithm is capable of calculating the lowest excited state at a certain symmetry, including both single and multireference excited states. The study investigated various UCC ansatze applied to VQE calculations on excited states, showing excellent agreement with results from classical machines.
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
(2021)
Article
Chemistry, Physical
Marvin H. Lechner, Robert Izsak, Marcel Nooijen, Frank Neese
Summary: The variant of the MR-EOMCC method introduces estimated amplitudes from perturbation theory, maintaining many-body formalism and state-universal properties with reduced computational costs. Performance evaluation against reference data on various test sets shows accuracy on par with multireference perturbation theories, especially useful in multistate situations where high precision is not required.
Article
Chemistry, Physical
Mahesh K. Sit, Subhasish Das, Kousik Samanta
Summary: High fidelity potential energy surfaces and nonadiabatic couplings were constructed using machine learning, and used to simulate the photodissociation of CH2OO. The results showed that there is an 88.4% probability of dissociation through the lower channel, and only a 11.6% probability of dissociation through the upper channel.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Yulin Sha, Zilong Guo, Yandong Han, Zheng Xue, Minjie Li, Yan Wan, Wensheng Yang, Xiaonan Ma
Summary: In this study, the excited-state proton transfer (ESPT) behavior between photoacids and silanols on mesostructured surfaces was investigated using steady and picosecond time-resolved fluorescence spectroscopy. It was found that deprotonated silanols acted as acceptors in ESPT, while protonated silanols affected ESPT by changing the basicity of the silica surface. The non-uniform distribution of Q(3)/Q(2) silanols on the surface led to heterogeneous properties, such as basicity, which greatly influenced the ESPT dynamics. This work provides new insights into the ESPT mechanism in mesostructured systems and inspiration for designing smart sensors and materials sensitive to proton concentration.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Benoit Braida, Zhenhua Chen, Wei Wu, Philippe C. Hiberty
Summary: A novel state-averaged version of ab initio nonorthogonal valence bond method is proposed for accurate theoretical studies of excited states in the valence bond framework. The method, called breathing-orbital valence bond (BOVB), shows the ability to accurately describe excited states and compute transition energies from the ground state, as demonstrated in tests on ozone and sulfur dioxide electronic states. The combination of compactness and accuracy in challenging cases is attributed to built-in dynamic correlation and flexibility in orbital selection.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Physical
Alexander N. Smirnov, Victor G. Solomonik
Summary: Accurate description of high-spin electronic excited states in lanthanide-containing molecules remains a challenge in electronic structure theory. This study develops a composite computational scheme to address this problem and applies it to investigate 12 electronic states of gadolinium monoxide. The results show that the proposed scheme can accurately describe the spectroscopic properties of these electronic states and evaluate the properties of previously unobserved states.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Review
Chemistry, Multidisciplinary
F. D. Vila, J. J. Kas, J. J. Rehr, K. Kowalski, B. Peng
Summary: Green's function methods provide a powerful framework for treating electron correlation in both excited states and x-ray spectra. A non-perturbative real-time coupled-cluster cumulant Green's function approach has been introduced to extend conventional methods, yielding better results for x-ray photoemission spectra and binding energies. This approach includes orthogonality and shake-up effects, enhancing the x-ray absorption spectrum near the edge.
FRONTIERS IN CHEMISTRY
(2021)
Article
Chemistry, Physical
Sebastian M. Thielen, Manuel Hodecker, Julia Piazolo, Dirk R. Rehn, Andreas Dreuw
Summary: The study introduces the core-valence separation (CVS) approximation applied to unitary coupled-cluster (UCC) theory for calculating core-excited states and simulating x-ray absorption spectroscopy (XAS). Results from CVS-UCC are compared to algebraic-diagrammatic construction methods and experimental data, showing its potential as a new approach for XAS calculations.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Junzi Liu, Lan Cheng
Summary: The article reviews the development of relativistic coupled-cluster and equation-of-motion coupled-cluster methods, focusing on recent efforts to improve computational efficiency and extend the methods to molecules containing heavy elements. Future directions for the development of these methods are also discussed.
WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE
(2021)