Joel M Bowman, Chen Qu, Riccardo Conte, Apurba Nandi, Paul L Houston, Qi Yu
{"title":"A perspective marking 20 years of using permutationally invariant polynomials for molecular potentials.","authors":"Joel M Bowman, Chen Qu, Riccardo Conte, Apurba Nandi, Paul L Houston, Qi Yu","doi":"10.1063/5.0268420","DOIUrl":"https://doi.org/10.1063/5.0268420","url":null,"abstract":"<p><p>This Perspective is focused on permutationally invariant polynomials (PIPs). Since their introduction in 2004 and first use in developing a fully permutationally invariant potential for the highly fluxional cation CH5+, PIPs have found widespread use in developing machine learned potentials (MLPs) for isolated molecules, chemical reactions, clusters, condensed phase, and materials. More than 100 potentials have been reported using PIPs. The popularity of PIPs for MLPs stems from their fundamental property of being invariant with respect to permutations of like atoms; this is a fundamental property of potential energy surfaces. This is achieved using global descriptors and, thus, without using an atom-centered approach (which is manifestly fully permutationally invariant). PIPs have been used directly for linear regression fitting of electronic energies and gradients for complex energy landscapes to chemical reactions with numerous product channels. PIPs have also been used as inputs to neural network and Gaussian process regression methods and in many-body (atom-centered, water monomer, etc.) applications, notably for gold standard potentials for water. Here, we focus on the progress and usage of PIPs since 2018, when the last review of PIPs was done by our group.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 18","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143966156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Samarjeet Prasad, Felix Aviat, James E Gonzales, Bernard R Brooks
{"title":"apoCHARMM: High-performance molecular dynamics simulations on GPUs for advanced simulation methods.","authors":"Samarjeet Prasad, Felix Aviat, James E Gonzales, Bernard R Brooks","doi":"10.1063/5.0264937","DOIUrl":"10.1063/5.0264937","url":null,"abstract":"<p><p>We present apoCHARMM, a high-performance molecular dynamics (MD) engine optimized for graphics processing unit (GPU) architectures, designed to accelerate the simulation of complex molecular systems. The distinctive features of apoCHARMM include single-GPU support for multiple Hamiltonians, computation of a full virial tensor for each Hamiltonian, and full support for orthorhombic periodic systems in both P1 and P21 space groups. Multiple Hamiltonians on a single GPU permit rapid single-GPU multi-dimensional replica exchange methods, multi-state enveloping distribution sampling methods, and several efficient free energy methods where efficiency is gained by eliminating post-processing requirements. The combination of these capabilities enables constant-pH molecular dynamics in explicit solvent with enveloping distribution sampling, where Hamiltonian replica exchange can be performed on a single GPU with minimal host-GPU memory transfers. A full atomic virial tensor allows support for many different pressure, surface tension, and temperature ensembles. Support for orthorhombic P21 systems allows for the simulation of lipid bilayers, where the two leaflets have equalized chemical potentials. apoCHARMM uses CUDA and modern C++ to enable efficient computation of energy, force, restraint, constraint, and integration calculations directly on the GPU. This GPU-exclusive design focus minimizes host-GPU memory transfers, ensuring optimal performance during simulations, with such transfers occurring only during logging or trajectory saving. Benchmark tests demonstrate that apoCHARMM achieves competitive or superior performance when compared to other GPU-based MD engines, positioning it as a versatile and useful tool for the molecular dynamics community.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 18","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12074570/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144020079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Facile synthesis of carbon-coated silicon nanocomposite with tremella-like porous structure for superior lithium-ion storage.","authors":"Lihua Ma, Jibin Tian, Xiaozhong Zhou","doi":"10.1063/5.0265543","DOIUrl":"https://doi.org/10.1063/5.0265543","url":null,"abstract":"<p><p>Silicon/carbon (Si/C) composites have been envisaged as one of the most promising anode materials for the next-generation lithium-ion batteries (LIBs) with high energy density, and constructing reasonable and cross-scale structures is crucial adjective for high-performance Si/C electrodes. Herein, a facile synthesis strategy was developed by combining gel coating, carbonization, and molten salt-assisted magnesiothermic reduction (MSA-MR), and a unique tremella-like Si/C composite with internal void structure (IV-Si/C) was successfully prepared. The working mechanisms of both sodium alginate (SA) and molten salt (NaCl) on the successful preparation of the target IV-Si/C nanocomposite were also investigated in detail. It was demonstrated that, α-L-guluronic (G) blocks in SA can be cross-linked with cations to promote the interactions with silicon dioxide (SiO2) particles, boosting uniform distribution of nanosized Si particles in the SA-derived carbon matrix. Meanwhile, NaCl generated from SA not only effectively boosted the crystallization of SiO2 during the high-temperature carbonization process but also can effectively inhibit the formation of inert SiC and strengthen reduction of carbon during the MSA-MR treatment, resulting in successful preparation of the tremella-like Si/C composite with abundant internal voids. Benefitting from its unique structure, when used as an alternative anode material for electrochemical lithium storage, the as-obtained IV-Si/C nanocomposite delivered a high reversible specific capacity of 1899.6 mAh g-1 with an initial Coulomb efficiency of 75.96% and superior rate capability and long-term cycling stability. This facile and low-cost synthesis strategy may shed light on the controllable preparation of functional nanomaterials with unique structures, especially high-performance Si/C anode materials for their large-scale application in LIBs.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 18","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143992883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Temperature-dependent local and global dynamics of atactic polystyrene: A coarse-grained molecular dynamics simulation study.","authors":"Jiaxian Zhang, Hongxia Guo","doi":"10.1063/5.0253982","DOIUrl":"https://doi.org/10.1063/5.0253982","url":null,"abstract":"<p><p>A systematic coarse-grained (CG) model, as a promising and helpful tool to access the accurate knowledge of the local and global polymer dynamics of real polymers, is required to preserve structural, thermodynamic, and dynamic properties of the underlying atomistic model over a wide temperature range. In the present work, to explore the temperature-dependent local and global dynamic properties of atactic polystyrene (PS) as well as the dynamic consistency of a PS CG model constructed via a structure- and thermodynamics-based CG approach with the united-atom (UA) counterpart, we have investigated and compared the translational and rotational dynamics of the two models in the scale from a single monomer to a global chain in a broad temperature range. The CG model accurately reproduces the time-dependent translational diffusion scaling and the shift from a multistep relaxation to a single-step long-time decay process with increasing span of bond vectors as the UA model. There exists the coupling of the conformational relaxation and diffusion of the PS chains to the local structural α-relaxation. Both diffusion coefficients and relaxation times of the UA and CG models show the same temperature dependence and follow a power-law relationship of mode-coupling theory. These findings advance our understanding of the complex dynamics of atactic PS and give a sounder basis for the further development of CG PS models with the (time-dependent) frictional correction to perform a quantitative study of structural relaxation and dynamical heterogeneity near glass transition temperature.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 18","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144016941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ketan Sharma, Oleg A Vasilyev, John F Stanton, Terry A Miller
{"title":"Ab initio simulation of spin-vibronic spectra of methoxy radical.","authors":"Ketan Sharma, Oleg A Vasilyev, John F Stanton, Terry A Miller","doi":"10.1063/5.0266367","DOIUrl":"https://doi.org/10.1063/5.0266367","url":null,"abstract":"<p><p>Despite the fact that experimental and theoretical work on the spectrum of methoxy has stretched from the microwave to the ultraviolet and proceeded for nearly 50 years, parts of the spectrum have remained a challenge to simulate theoretically and make reliable line-by-line assignments. The spectral complexity arises because the radical has a non-zero electron spin and significant vibronic coupling between the two electronic components of the ground state due to the presence of a conical intersection. This work describes a completely ab initio effort to understand and assign the spin-vibronic levels of the X̃2E state from 0 to above 3000 cm-1, a region that includes the fundamental transitions of the C-H symmetric and asymmetric stretches that have not previously been identified uniquely. A potential energy surface for methoxy was calculated at the equation-of-motion (EOM)-coupled cluster singles, doubles, and triples (CCSDT)/atomic natural orbital (ANO1) level of theory. Subsequently, this potential energy surface was fit to a quartic power series expansion of all nine vibrational normal coordinates (as determined at the minimum of the conical intersection) by the use of a machine-learning-based algorithm. After the addition of spin-orbit coupling, the spin-vibronic problem was solved using both the Krylov-Schur and Lanczos algorithms with the SOCJT3 software to converge eigenvalues up to 3500 cm-1 and their eigenvectors. The latter were used, in conjunction with the calculated dipole moment and its derivatives (calculated using finite differences at the EOM-CCSDT/ANO1 level), to determine spectral intensities for the spin-vibronic spectra. The calculated transition frequencies and intensities were used to simulate and assign the observed transitions of the spin-vibronic spectra of the radical. The credibility of the assignments and their significance is discussed in detail.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 18","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144020599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ab initio phase diagrams of binary alloys in the low solute concentration limit.","authors":"Shambhu Bhandari Sharma, Shailesh Mehta, Dario Alfè","doi":"10.1063/5.0264856","DOIUrl":"https://doi.org/10.1063/5.0264856","url":null,"abstract":"<p><p>Phase diagrams are crucial to the design of new materials, to understand their phase stability and metastability under different thermodynamic conditions, such as composition, temperature, and pressure. Here, we use an ab initio approach to study the phase diagram of a binary alloy within the low concentration limit of a solute. Using the ab initio molecular dynamics calculations based on density functional theory, we estimate the solute partitioning ratios in solid-liquid phase equilibria. The chemical potential difference between the solvent and solute atoms in both solid and liquid phases is calculated using thermodynamic integration. As an illustration of the techniques, we have applied this method to reproduce the phase diagram of the Al-Mg alloy at zero pressure. We also compute the ab initio solid-liquid coexistence curve of pure Al by applying the phase-coexistence method with the free energy correction technique. The calculated results are in close agreement with the experiment, demonstrating the reliability of the models.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 18","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143967694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xin Jing, Abhiraj Sharma, John E Pask, Phanish Suryanarayana
{"title":"GPU acceleration of hybrid functional calculations in the SPARC electronic structure code.","authors":"Xin Jing, Abhiraj Sharma, John E Pask, Phanish Suryanarayana","doi":"10.1063/5.0260892","DOIUrl":"https://doi.org/10.1063/5.0260892","url":null,"abstract":"<p><p>We present a Graphics Processing Unit (GPU)-accelerated version of the real-space SPARC electronic structure code for performing hybrid functional calculations in generalized Kohn-Sham density functional theory. In particular, we develop a batch variant of the recently formulated Kronecker product-based linear solver for the simultaneous solution of multiple linear systems. We then develop a modular, math kernel based implementation for hybrid functionals on NVIDIA architectures, where computationally intensive operations are offloaded to the GPUs, while the remaining workload is handled by the central processing units (CPUs). Considering bulk and slab examples, we demonstrate that GPUs enable up to 8× speedup in node-hours and 80× in core-hours compared to CPU-only execution, reducing the time to solution on V100 GPUs to around 300 s for a metallic system with over 6000 electrons, and significantly reducing the computational resources required for a given wall time.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 18","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144002321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sanchayeeta Jana, Simon Durst, Lucas Ludwig, Markus Lippitz
{"title":"Overcoming experimental obstacles in two-dimensional spectroscopy of a single molecule.","authors":"Sanchayeeta Jana, Simon Durst, Lucas Ludwig, Markus Lippitz","doi":"10.1063/5.0261813","DOIUrl":"https://doi.org/10.1063/5.0261813","url":null,"abstract":"<p><p>Two-dimensional electronic spectroscopy provides information on coupling and energy transfer between excited states on ultrafast timescales. Only recently, incoherent fluorescence detection has made it possible to combine this method with single-molecule optical spectroscopy to reach the ultimate limit of sensitivity. The main obstacle has been the low number of photons detected due to limited photostability. Here, we discuss the key experimental choices that allowed us to overcome these obstacles: broadband acousto-optic modulation, accurate phase-locked loops, photon-counting lock-in detection, delay stage linearization, and detector dead-time compensation. We demonstrate how the acquired photon stream data can be used to post-select detection events according to specific criteria.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 18","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143967920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alessandro Coretti, Sebastian Falkner, Phillip L Geissler, Christoph Dellago
{"title":"Learning mappings between equilibrium states of liquid systems using normalizing flows.","authors":"Alessandro Coretti, Sebastian Falkner, Phillip L Geissler, Christoph Dellago","doi":"10.1063/5.0253034","DOIUrl":"https://doi.org/10.1063/5.0253034","url":null,"abstract":"<p><p>Generative models and, in particular, normalizing flows are a promising tool in statistical mechanics to address the sampling problem in condensed-matter systems. In this work, we investigate the potential of normalizing flows to learn a transformation to map different liquid systems into each other while allowing at the same time to obtain an unbiased equilibrium distribution. We apply this methodology to the mapping of a small system of fully repulsive disks modeled via the Weeks-Chandler-Andersen potential into a Lennard-Jones system in the liquid phase at different coordinates in the phase diagram. We obtain an improvement in the relative effective sample size of the generated distribution up to a factor of six compared to direct reweighting. We show that this factor can have a strong dependency on the thermodynamic parameters of the source and target system.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 18","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144020554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Probing intrinsic noise correlation time in non-Markovian diffusive systems.","authors":"Ming-Gen Li, Xin-Yao Dong, He-Chuan Liu, Jing-Dong Bao, Peng-Cheng Li, Li-Ming Fan","doi":"10.1063/5.0266278","DOIUrl":"https://doi.org/10.1063/5.0266278","url":null,"abstract":"<p><p>The generalized Langevin equation describes molecular motion in complex systems using memory and random noise terms. Memory effects, the inherent time correlation in random noise, significantly influence molecular diffusive behaviors. However, estimating the intrinsic noise correlation time remains challenging because of difficulties in measuring the memory term. We propose a metric to probe the noise correlation time based on the deviation between characteristic times of configurational diffusion and \"diffusion motion\" in the kinetic energy space. This approach stems from the observation that memory effects delay relaxation time between displacement and velocity response functions. Our metric relies solely on the velocity autocorrelation function, commonly used in experimental model parameterization. Both analytical and numerical results for various physical models demonstrate its effectiveness in probing noise correlation time. Furthermore, we apply this metric to study complex diffusive phenomena, including non-exponential relaxation in molecular hydrodynamics and anomalous diffusion in crowded environments. By comparing with system's relaxation time, we reveal that long-range noise correlations play a key role in these non-trivial diffusive phenomena.</p>","PeriodicalId":15313,"journal":{"name":"Journal of Chemical Physics","volume":"162 18","pages":""},"PeriodicalIF":3.1,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144038697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}