Article
Chemistry, Physical
Bing Huang, O. Anatole von Lilienfeld, Jaron T. Krogel, Anouar Benali
Summary: Quantum diffusion Monte Carlo (DMC) has shown great potential in predicting the energetics and properties of molecules and solids through solving the electronic many-body Schrödinger equation. When coupled with quantum machine learning (QML), DMC can alleviate computational burden, making it a promising method for large systems. Three crucial approximations, including fixed-node approximation, universal reference for chemical bond dissociation energies, and scalable minimal amons-set-based QML (AQML) models, are discussed. Numerical evidence suggests that even modestly sized QMC training data sets can accurately predict total energies throughout chemical space.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Physics, Multidisciplinary
Julia A. Davies, Christoph Schran, Fabien Brieuc, Dominik Marx, Andrew M. Ellis
Summary: In this study, infrared spectroscopy is used to investigate 4HeN center dot center dot center dot H3O+ complexes. It is found that the rotational behavior of H3O+ undergoes significant changes as 4He atoms are added.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Oliver A. Bramley, Timothy J. H. Hele, Dmitrii Shalashilin
Summary: Zombie states are a formalism that describes coupled coherent fermionic states in a computationally tractable manner. This study extends the previous work on Zombie states and develops efficient algorithms for evaluating operators and addressing normalization. It also presents techniques for improving accuracy and calculating low-lying excited states.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
Jan Kessler, Francesco Calcavecchia, Thomas D. Kuehne
Summary: Inspired by the universal approximation theorem and the widespread adoption of artificial neural network techniques, feed-forward neural networks are proposed as a general purpose trial wave function for quantum Monte Carlo simulations of continuous many-body systems. The accuracy of the trial wave functions was demonstrated by studying an exactly solvable model system of two trapped interacting particles and the hydrogen dimer. The whole many-body wave function can be represented by a neural network for simple model systems, while the antisymmetry condition of non-trivial fermionic systems is incorporated by means of a Slater determinant.
ADVANCED THEORY AND SIMULATIONS
(2021)
Article
Materials Science, Multidisciplinary
Yuichi Motoyama, Kazuyoshi Yoshimi, Junya Otsuki
Summary: Analytic continuation from the imaginary-time Green's function to the spectral function is crucial for studying the dynamical properties of quantum many-body systems. However, this process is unstable and has advantages and disadvantages. Combining SpM AC with Pade approximation in the SpM-Pade method can provide more accurate and stable results.
Article
Chemistry, Physical
Anthony Scemama, Andreas Savin
Summary: This article calculates the probabilities of finding a chosen number of electrons in flexible domains of space using highly correlated wave functions. Quantum mechanics can increase the probabilities of chemically relevant electron arrangements in these regions. However, the probability of having a specific arrangement, such as chemical formulas (bonds or atoms), is often low despite being maximal. It is useful to consider alternative distributions of electrons and to include exchanges of electrons between different types of regions.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
Yan-Cheng Wang, Meng Cheng, William Witczak-Krempa, Zi Yang Meng
Summary: The experimental discovery of Anyons in two-dimensional electron gases has opened up new possibilities for studying quantum particles beyond bosons and fermions. Large-scale quantum Monte Carlo simulations have revealed unique conductivity properties near a phase transition, with implications for quantum materials research.
NATURE COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Jonas Feldt, Antoine Bienvenu, Roland Assaraf
Summary: In this paper, a new estimator in the variational Monte Carlo framework is proposed, which utilizes numerically cheap single-core subsamplings to improve the estimation of molecular properties. Furthermore, a spin-dependent core definition is introduced to simplify the algorithm and enhance its efficiency.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Giovani L. Rech, Andre L. Martinotto, Janete E. Zorzi, Claudio A. Perottoni
Summary: The relative stability between the crystal structure of alpha-F-2, space group C2/c, and a hypothesized high-pressure phase, space group Cmce, was investigated using Density Functional Theory and Quantum Monte Carlo calculations. The analysis of the phonon dispersion spectra showed that the Cmce phase exhibits dynamical instability near the Gamma-point at ambient pressure, which disappears under increasing pressure. This instability is attributed to the absence of sigma-holes in the fluorine molecule, resulting in repulsive head-to-head interactions between molecules.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Tina N. Mihm, William Z. Van Benschoten, James J. Shepherd
Summary: A new approach using low-cost calculations was developed to find a twist angle that matches the coupled cluster doubles energy in a finite unit cell. The method was shown to have comparable accuracy with exact methods beyond coupled cluster doubles theory. Additionally, for small system sizes, the same twist angle can be found by comparing energies directly, suggesting a potential route towards twist angle selection.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Leon Otis, Eric Neuscamman
Summary: We discuss recent progress in excited-state-specific quantum chemistry and quantum Monte Carlo and show how combining methods from these fields can predict excited states accurately. Important advances in both fields include improved optimization methods, handling of complicated wave function forms, and balancing the quality of wave functions for ground and excited states. Demonstrations using a combination of specific quantum chemistry and variational Monte Carlo show that this approach is more reliable and accurate than other high-level methods and can provide clarity in cases where existing methods do not agree.
WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE
(2023)
Article
Physics, Multidisciplinary
Ivan P. Christov
Summary: This study compares the effects of spatial nonlocality and nonlocal causality on two entangled electrons. It finds that spatial entanglement can be accurately predicted using the TDQMC method, while nonlocal causality only leads to small oscillations in the observed electron trajectories.
Article
Physics, Multidisciplinary
Daniel K. Ruttley, Alexander Guttridge, Stefan Spence, Robert C. Bird, Ruth Le Sueur, Jeremy M. Hutson, Simon L. Cornish
Summary: We successfully form a single RbCs molecule by merging two optical tweezers containing a single Rb atom and a single Cs atom. Both atoms are initially in the ground states of their respective tweezers. By measuring the binding energy, we confirm molecule formation and determine its state. We show that the probability of molecule formation can be controlled by tuning the confinement of the traps during the merging process, in agreement with calculations. We demonstrate that the conversion efficiency from atoms to molecules using this technique is comparable to magnetoassociation.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Yue Jiang, Liang Shi, Naibo Chen, Laigui Hu, Wenchong Wang, Qingmiao Nie, Bo Yan
Summary: Micro-patterning of organic thin films is crucial for organic electronics. Different techniques have been developed for patterning organic films, including area-selective growth. The growth behavior of different molecule configurations on patterned surfaces has been investigated experimentally. By controlling diffusion and nucleation, separation of multi-species molecules at the micro-scale has been demonstrated. Kinetic Monte Carlo simulations have been used to study the molecular dynamics of non-planar molecules, but little attention has been given to step-edge induced area-selective growth. In this study, a coarse-grained anisotropic interaction model was introduced in the kinetic Monte Carlo algorithm to simulate step-edge induced area-selective growth. The results showed that the edges of electrode patterns become preferential nucleation sites, followed by lateral growth due to strong 7C-7C interactions. The simulations also demonstrated the separation of different particles on designed locations, similar to experimental observations. These results validate the kinetic Monte Carlo simulation as a powerful tool for studying area-selective growth of anisotropic molecules.
RESULTS IN PHYSICS
(2023)
Article
Chemistry, Physical
Francisco Ballesteros, Shelbie Dunivan, Ka Un Lao
Summary: This work reports benchmark binding energies for dispersion-bound complexes, DNA-ellipticine intercalation complex, and buckycatcher-C-60 complex with 120 heavy atoms using a focal-point method based on MP2 and CCSD(T) extrapolated to the CBS limit. The discrepancies between CCSD(T) and fixed-node diffusion Monte Carlo methods are substantial for large noncovalent complexes.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Correction
Chemistry, Physical
Chen Luo, Yan Shao, Hua Yu, Hong-zhi Ma, Yu-hao Zhang, Long Gu, Bo Yin, Ming-bo Yang
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Stefano Borocci, Armando Camerlingo, Felice Grandinetti, Maria Rutigliano, Nico Sanna
Summary: The complexes of He, Ne, Ar, Kr, and Xe with B3N3H6 were investigated using MP2, CCSD(T), and SAPT ab initio methods. The complexes can be described as mono-, di-, and tri-coordinated to the N atoms, with stability following the order N-mono < N-di < N-tri. The interactions are dominated by dispersion and the binding energies are within the range of 1 or 2 kcal mol(-1). The results were compared with a recent DFT study on larger BN sheets complexes [Phys. Chem. Chem. Phys. 24 (2022) 2554-2566.].
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
V. Nagarajan, R. Bhuvaneswari, R. Chandiramouli
Summary: In this study, stable phosphoborane was used as a sensor to detect isobutane and n-propane in Liquefied Petroleum Gas (LPG). Phosphoborane demonstrated structural stability and semiconducting nature, and exhibited promising adsorption properties for the LPG molecules.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Xiaoxi Xu, Zijiang Yang, Bayaer Buren, Maodu Chen
Summary: In this study, the time-dependent wave packet method was used to investigate the reaction channels and mechanisms of Ca+ + HD. The results show that the CaH+ + D reaction channel plays a primary role, which is consistent with experimental results. Complex forming and direct-abstraction reaction mechanisms exist in this reaction process.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Keshab Pandey, Hae Kyung Jeong
Summary: A free-standing silicon-carbon nanofiber composite film was synthesized and investigated for supercapacitor applications. It exhibited high specific capacitance, energy density, and power density. After 5000 cycles, the film showed excellent specific capacitance retention and Coulombic efficiency.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Xinyu Zhang, Haosong Li, Xiaoyu Cao, Jing Gao, Yong Wei, Jianzhuo Zhu
Summary: The evaporation behavior of nanosized water aggregations on two-dimensional electroneutral solid surfaces with different surface polar unit densities was investigated. The results showed that the evaporation rate changes non-monotonically with the surface polar unit density, and the minimum evaporation rate is obtained when the surface has a modest surface polar unit ratio of 66.7%.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Yanyan Xu, Rui Dai, Xiaojie Wang, Zhijun Qiao, Haowei Wen, Dianbo Ruan, Yuzuo Wang
Summary: This article presents an innovative solvothermal sodium insertion method for synthesizing Triphylite-NaFePO4, which demonstrates optimal electrochemical performance in sodium-ion batteries.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Meiyi Jiang, Kun Yang, Yancheng Liu, Li Yao
Summary: The geometric structure and electronic properties of transition metal M (M = Cu, Fe, Mn)-TiO2 (101) surface adsorbed by NO2 and N2O were calculated by density functional theory (DFT) and DFT + U theory. The results showed that the adsorption of NO2 and N2O on Mn and Fe atoms is more stable, and a large number of active electrons are formed around these atoms, facilitating the catalytic reactions.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Sergey A. Vyrko, Yulia G. Polynskaya, Nikita A. Matsokin, Andrey M. Popov, Andrey A. Knizhnik, Nikolai A. Poklonski, Yurii E. Lozovik
Summary: In this study, carbon nanobracelets, which are cyclic molecules composed of alternating polycyclic regions and double carbon chains, were investigated using spin-polarized density functional theory. The results show that carbon nanobracelets with odd number of monomers exhibit distinct electronic energy levels, band gaps, and carbon chain deformation compared to those with even number of monomers.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Chanchan Wang, Quan Yang, Yanzhi Ding, Xiaoyong Lu, Dong Tian
Summary: It has been found that the introduction of buffer layers improves the electrical performance of solid oxide fuel cells (SSOFCs). In this study, varying ratios of Gd-doped CeO2 were used as buffer layers in YSZ-based SSOFCs. The results demonstrate that the performance of SSOFCs is enhanced when a buffer layer is added, with the highest performance achieved using Ce0.8Gd0.2O2-delta (GDC20) as the buffer layer. This suggests that the use of GDC series buffer layers is an attractive strategy to optimize performance loss due to electrolyte-electrode interactions.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Wang Li, Yi-Fan Zhang, Jia-Bin Huang, Chang-Yang Wang, Feng Zhang, Jiu-Zhong Yang, Long Zhao
Summary: The gas-phase reaction of propargyl with vinylacetylene was investigated using synchrotron photoionization and molecular-beam mass spectrometry methodologies. The formation mechanisms of the resulting cyclic structures were examined using quantum computations. Two previously unidentified isomers were detected and identified for the first time.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Avijit Pramanik, Sanchita Kundu, Olorunsola Praise Kolawole, Kaelin Gates, Paresh Chandra Ray
Summary: This study investigates the influence of aspect ratio and quantum confinement on the single-photon and two-photon absorption cross-section of perovskite CsPbI3 nanorods. Experimental data shows that CsPbI3 nanorods have an extremely high two-photon absorption cross-section, significantly surpassing organic chromophores and other CsPbBr3 nanocrystals. Moreover, adjusting the aspect ratio can significantly enhance the absorption ability. Additionally, the study also reveals a moderate quantum confinement effect on the single-photon and two-photon absorption cross-section of the nanorods.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Hyon-Tae Pak, Jin-A Choe, Kyong-Sik Ju, Yong -Son Rim
Summary: Drug-loaded cellulose diacetate (CDA) membranes were prepared using different compositions of mixed solvent. The microstructure and performance of the membranes were investigated, and a method to predict drug release properties was proposed. The results showed that the composition of the mixed solvent significantly affected the overall performance of CDA membranes, and the release rates of drugs were related to Δdelta and the intrinsic viscosity of CDA.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Gabriella E. Ravin, E. Curotto
Summary: We have developed a systematic approach to optimize the training set sizes for neural networks in fitting ab initio potential energy surfaces. Using this approach, we have constructed several spectroscopic quality potential energy surfaces for [Li(H2)n]+, n = 1 - 9. The ground state properties have been computed for all the systems and selected states.
CHEMICAL PHYSICS LETTERS
(2024)
Article
Chemistry, Physical
Guohua Xu, Lei Xu, Feng Zhang, Chunling Yu, Yu Song
Summary: NiS1.03@Ni7S6/carbon composite was successfully prepared using corn stalk as a carbon source via a simple adsorption-sulphurization process. The composite exhibited a specific capacitance of 1554.6 F/g at 1 A/g as a supercapacitor electrode, with a capacitance retention rate of 80.4% after 5000 cycles. Furthermore, the NiS1.03@Ni7S6/carbon//AC asymmetric supercapacitor showed a high energy density of 41.2 Wh kg-1 at a power density of 750 W kg-1, and excellent cycling stability with 86.8% capacitance retention after 10,000 cycles.
CHEMICAL PHYSICS LETTERS
(2024)