The Journal of Physical Chemistry A最新文献

{"title":"Precise Determination of Excited State Rotational Constants and Black-Body Thermometry in Coulomb Crystals of Ca+ and CaH+","authors":"Swapnil Patel,&nbsp; and ,&nbsp;Kenneth R. Brown*,&nbsp;","doi":"10.1021/acs.jpca.5c0022910.1021/acs.jpca.5c00229","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00229https://doi.org/10.1021/acs.jpca.5c00229","url":null,"abstract":"<p >We present high-resolution rovibronic spectroscopy of calcium monohydride molecular ions (CaH⁺) cotrapped in a Coulomb crystal with calcium ions (⁴⁰Ca⁺), focusing on rotational transitions in the <i></i><math><mo>|</mo><msup><mi>X</mi><mn>1</mn></msup><msup><mi>Σ</mi><mo>+</mo></msup></math>, <i>ν</i>″ = 0⟩ → |<i>A</i>¹Σ⁺, <i>ν</i>′ = 2⟩ manifold. By resolving individual P and R branch transitions with record precision and using Fortrat analysis, we extract key spectroscopic constants for the excited state |<i>A</i>¹Σ⁺, <i>ν</i>′ = 2⟩, specifically, the band origin, the rotational constant, and the centrifugal correction. Additionally, we demonstrate the application of high-resolution rotational spectroscopy of CaH⁺ presented here as an in situ probe of the local environmental temperature. We correlate the relative amplitudes of the observed transitions to the underlying thermalized ground-state rotational population distribution and extract the blackbody radiation (BBR) temperature.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 16","pages":"3624–3629 3624–3629"},"PeriodicalIF":2.7,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863214","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":"Unified Framework for Molecular Response Functions of Different Electronic-Structure Models","authors":"Bin Gao*,&nbsp; and ,&nbsp;Magnus Ringholm,&nbsp;","doi":"10.1021/acs.jpca.4c0778910.1021/acs.jpca.4c07789","DOIUrl":"https://doi.org/10.1021/acs.jpca.4c07789https://doi.org/10.1021/acs.jpca.4c07789","url":null,"abstract":"<p >A unified framework─SymResponse─has been developed as a versatile tool to aid the implementation of response theory for different electronic-structure models. The framework manipulates the quasi-energy formulation of response theory at a symbolic level by building on top of other well-developed symbolic libraries. Response functions can therefore be nicely represented by “symbolic expressions,” which can be further evaluated numerically by users by developing their own evaluation routines with the assistance of SymResponse. The design of SymResponse makes it extensible to different electronic-structure models with only a moderate further amount of development effort. Response theory at Hartree–Fock, density functional theory, and coupled-cluster levels has been implemented in the present work as a demonstration, where elimination rules [<contrib-group><span>Kristensen, K.</span></contrib-group> <cite><i>J. Chem. Phys.</i></cite> <span>2008</span>, <em>129</em>, <elocation-id>214103</elocation-id>] can also be applied to offer the possibility to reduce the size of computational tasks.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 16","pages":"3709–3721 3709–3721"},"PeriodicalIF":2.7,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.jpca.4c07789","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863215","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":"The Many-Body Expansion for Metals: II. Nonadditive Terms in Clusters Composed of Metals with ns1, ns2, and ns2p1 Configurations","authors":"Demeter Tzeli*,&nbsp;Joani Mato and Sotiris S. Xantheas*,&nbsp;","doi":"10.1021/acs.jpca.5c0106610.1021/acs.jpca.5c01066","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c01066https://doi.org/10.1021/acs.jpca.5c01066","url":null,"abstract":"<p >The many-body expansion (MBE) was applied to homometallic and heterometallic trimers of metals with n<i>s</i>¹, n<i>s</i>², and n<i>s</i>²<i>p</i>¹ configurations to investigate its convergence, the magnitude and nature (stabilizing/destabilizing) of the individual terms and seek an understanding of their variation across the different families of clusters. In particular, we examined the series of alkali metals (Li₃, Na₃, K₃, Li₂Na, LiNa₂), alkali metal borides (Li₂B and LiB₂), and alkaline earth metals (Be₃, Be₂Mg, BeMg₃, and Mg₃) trimers, as well as sodium clusters Na<i>_n</i>, <i>n</i> = 2–5. We found that there is no uniform contribution (stabilizing or destabilizing) across the series in the different families of trimers. For instance, the 2-B term stabilizes the ground states of the Na₃ (doublet), Na₄ (singlet), and Na₅ (doublet) clusters, and the 3-B term destabilizes them; however, the opposite holds for the quartet state of the Li₃, Li₂Na, LiNa₂, and Na₃ clusters (destabilizing 2-B, stabilizing 3-B). Substituting Li with B in the quartet state of Li₃ results in a significant reduction of the 3-B term amounting to 16% (Li₂B) and 5% (LiB₃) of the binding energy. On the contrary, the ground states of the alkaline earth metal clusters (Be₃, Be₂Mg, BeMg₃, and Mg₃) are stabilized by the 3-B term, while the 2-B term destabilizes them. Overall, we find that the 3-B terms significantly stabilize the high-spin multiplicity states of the n<i>s</i>¹ configurations and the low-spin states of the n<i>s</i>² configurations. Finally, as the size of the metal increases, the contribution of the 3-B term to the binding energy decreases due to the longer metal–metal bond distances.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 16","pages":"3648–3662 3648–3662"},"PeriodicalIF":2.7,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863177","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":"Accurate and Affordable Simulation of Molecular Infrared Spectra with AIQM Models","authors":"Yi-Fan Hou,&nbsp;Cheng Wang and Pavlo O. Dral*,&nbsp;","doi":"10.1021/acs.jpca.5c0014610.1021/acs.jpca.5c00146","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00146https://doi.org/10.1021/acs.jpca.5c00146","url":null,"abstract":"<p >Infrared (IR) spectroscopy is a potent tool for identifying molecular structures and studying the chemical properties of compounds, and hence, various theoretical approaches have been developed to simulate and predict the IR spectra. However, the theoretical approaches based on quantum chemical calculations suffer from high computational cost (e.g., density functional theory, DFT) or insufficient accuracy (e.g., semiempirical methods orders of magnitude faster than DFT). Here, we introduce a new approach, based on the universal machine learning (ML) models of the AIQM series targeting CCSD(T)/CBS level, that can deliver molecular IR spectra with accuracy close to DFT (compared to the experiment) and the speed close to a semiempirical GFN2-xTB method. This approach is based on the harmonic oscillator approximation with the frequency scaling factors fitted to experimental data. While the benchmarks reported here are focused on harmonic IR spectra, our implementation supports anharmonic spectra simulations via molecular dynamics and VPT2. These implementations are available in MLatom as described in https://github.com/dralgroup/mlatom and can be performed online via a web browser.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 16","pages":"3613–3623 3613–3623"},"PeriodicalIF":2.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863262","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":"Many-Body Basis Set Amelioration Method for Incremental Full Configuration Interaction","authors":"Jeffrey Hatch,&nbsp;Alan E. Rask,&nbsp;Duy-Khoi Dang and Paul M. Zimmerman*,&nbsp;","doi":"10.1021/acs.jpca.5c0152110.1021/acs.jpca.5c01521","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c01521https://doi.org/10.1021/acs.jpca.5c01521","url":null,"abstract":"<p >Incremental full configuration interaction (iFCI) is a polynomial-cost electronic structure method that systematically approaches the FCI limit by employing the method of increments to solve the Schrödinger equation through a many-body expansion. This article introduces the many-body basis set amelioration (MBBSA) method, which is designed to allow iFCI to be applicable to larger atomic orbital basis sets. MBBSA uses a series of inexpensive iFCI calculations to approximate the correlation energy that would be found using a more expensive, highly accurate iFCI calculation. When compared to standard iFCI computations on smaller molecules in triple-ζ and larger basis sets, MBBSA provides approximations to the total and relative energies within chemical accuracy. MBBSA exhibits a reduced cost of between 60 and 92% when compared to standard iFCI calculations, with larger systems experiencing the largest benefit. Tests of MBBSA on two reactions that involve highly correlated systems, the automerization of cyclobutadiene and a Criegee intermediate reaction, show that MBBSA has practical utility for studying realistic chemistries.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 16","pages":"3743–3753 3743–3753"},"PeriodicalIF":2.7,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863257","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":"Exploring Vinylidene/Acetylene Isomerization by Photoelectron Spectroscopy of Vibrationally Excited Vinylidene Anions","authors":"Martin DeWitt,&nbsp;Dongzheng Yang,&nbsp;Jascha A. Lau,&nbsp;Korina Vlahos,&nbsp;Hua Guo* and Daniel M. Neumark*,&nbsp;","doi":"10.1021/acs.jpca.5c0165610.1021/acs.jpca.5c01656","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c01656https://doi.org/10.1021/acs.jpca.5c01656","url":null,"abstract":"<p >In order to explore the vibrational levels of vinylidene (H₂CC) and their possible couplings with acetylene (HCCH), we investigate the effect of infrared (IR) vibrational pre-excitation on the high-resolution photoelectron spectra of the vinylidene anion (H₂CC^-) and its deuterated isotopologue (D₂CC^-). The photoelectron spectra are obtained using slow electron velocity-map imaging of cryogenically cooled anions (cryo-SEVI); here, cold anions are vibrationally excited by an IR laser pulse prior to photodetachment (IR cryo-SEVI). Infrared action spectra of the anion CH₂ stretching fundamentals are measured by monitoring growth and depletion of features in photoelectron spectra as the IR laser is tuned, yielding excitation frequencies of the symmetric (ν₁) and antisymmetric (ν₅) CH₂ stretching modes of 2590 ± 2 and 2658 ± 2 cm^–1, respectively. We then use IR cryo-SEVI to explore the effect of vibrational excitation of the two modes on the anion photoelectron spectrum. Interpretation of these spectra is facilitated by quantum calculations performed for each isotopologue on accurate six-dimensional potential energy surfaces of both neutral and anionic vinylidene. IR cryo-SEVI spectra resulting from excitation of these two close-lying anion vibrations are noticeably different. Excitation of the ν₁ mode leads to several new features that appear in the photoelectron spectra which closely match the Franck–Condon allowed transitions predicted by theory. Excitation of the ν₅ mode in H₂CC^- reveals complicated spectral features in the vicinity of the 5₁¹ sequence band that are not seen for D₂CC^-. These are explained by a combination of anharmonic coupling between ν₅ and ν₆ (CH₂ rock) states in neutral H₂CC and possible coupling to the HCCH isomer.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 16","pages":"3682–3695 3682–3695"},"PeriodicalIF":2.7,"publicationDate":"2025-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863235","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":"NMR Crystallography Structure Determinations with 1H Chemical Shifts. GIPAW DFT Calculation Quality Can Be Substantially Degraded, but Nearly Identical Outputs Relative to Benchmark Computations Are Obtained: Why and So What?","authors":"Cory M. Widdifield*,&nbsp;Navjot Kaur and Khoa Minh Nghi Nguyen,&nbsp;","doi":"10.1021/acs.jpca.5c0002510.1021/acs.jpca.5c00025","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c00025https://doi.org/10.1021/acs.jpca.5c00025","url":null,"abstract":"&lt;p &gt;Nuclear magnetic resonance (NMR) crystallography may be used in various solid-state structural characterization tasks. For organic compounds in this context, proton isotropic chemical shifts [δ&lt;sub&gt;iso&lt;/sub&gt;(&lt;sup&gt;1&lt;/sup&gt;H)] are routinely used. It is typical to pair experimentally measured proton δ&lt;sub&gt;iso&lt;/sub&gt; values with δ&lt;sub&gt;iso&lt;/sub&gt; values that were computationally generated from crystal structure models. This can yield a δ&lt;sub&gt;iso&lt;/sub&gt;(&lt;sup&gt;1&lt;/sup&gt;H) root-mean-squared deviation (RMSD) value for each crystal structure model. In this study, we monitor the way in which gauge including projector augmented wave (GIPAW) density functional theory (DFT) computations of &lt;sup&gt;1&lt;/sup&gt;H δ&lt;sub&gt;iso&lt;/sub&gt; values can be influenced by the quality of the computational input parameters. We consider 126 computationally generated (using crystal structure prediction, CSP) crystal structures for three molecules: cocaine (30 structures), flutamide (21 structures), and ampicillin (75 structures). The quality parameters selected are the plane wave energy cutoff (&lt;i&gt;E&lt;/i&gt;&lt;sub&gt;cut&lt;/sub&gt;), and the &lt;i&gt;k&lt;/i&gt;-point grid used to sample reciprocal (i.e., momentum) space. We also probe the utility of performing one-parameter and two-parameter linear mappings for transforming computed hydrogen isotropic magnetic shielding values (σ&lt;sub&gt;iso&lt;/sub&gt;) into computed δ&lt;sub&gt;iso&lt;/sub&gt;(&lt;sup&gt;1&lt;/sup&gt;H) values. We find that both &lt;i&gt;E&lt;/i&gt;&lt;sub&gt;cut&lt;/sub&gt; and the &lt;i&gt;k&lt;/i&gt;-point grid can be degraded substantially (e.g., &lt;i&gt;E&lt;/i&gt;&lt;sub&gt;cut&lt;/sub&gt; ∼ 25 Ry) and yet still produce very similar computed δ&lt;sub&gt;iso&lt;/sub&gt;(&lt;sup&gt;1&lt;/sup&gt;H) values. We consider the mechanisms under GIPAW DFT that contribute to computed hydrogen σ&lt;sub&gt;iso&lt;/sub&gt; values to help understand this robustness: many contributions are zero or cancel out when converting σ&lt;sub&gt;iso&lt;/sub&gt; values to δ&lt;sub&gt;iso&lt;/sub&gt;(&lt;sup&gt;1&lt;/sup&gt;H) values &lt;i&gt;via&lt;/i&gt; the linear mapping. The robust nature of computed δ&lt;sub&gt;iso&lt;/sub&gt;(&lt;sup&gt;1&lt;/sup&gt;H) values leads to consistent estimates of δ&lt;sub&gt;iso&lt;/sub&gt;(&lt;sup&gt;1&lt;/sup&gt;H) RMSD values. It is then demonstrated using cocaine and flutamide that when δ&lt;sub&gt;iso&lt;/sub&gt;(&lt;sup&gt;1&lt;/sup&gt;H) RMSD values are used in NMR crystallography tasks such as structure selection/determination, the quality of the GIPAW DFT computation can be severely degraded and still produce identical outcomes to those that used a more computationally intensive protocol. Ampicillin is selected as a practical example to probe how our findings might reasonably be applied in the structure determination of a complex organic molecule. We propose that relatively modest quality GIPAW DFT computations (i.e., &lt;i&gt;E&lt;/i&gt;&lt;sub&gt;cut&lt;/sub&gt; = 35 Ry and a 1 × 1 × 1 &lt;i&gt;k&lt;/i&gt;-point grid) may be used to first filter out obviously poor structure candidates. Subsequently, slightly higher quality GIPAW DFT computations can be used for structure selection/determination. Our findings indicate that it should be possible to, on average, reduce the computational resources required i","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 16","pages":"3722–3742 3722–3742"},"PeriodicalIF":2.7,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863188","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":"An Insight into the Crystal Growth of 7-Aminodeacetoxycephalosporanic Acid from the Perspective of the Growth Unit","authors":"Zhijia Hao,&nbsp;Xiaowei Cheng*,&nbsp;Yuan Han,&nbsp;Peizhou Li,&nbsp;Shiyu Sun,&nbsp;Baoshu Liu and Hua Sun*,&nbsp;","doi":"10.1021/acs.jpca.5c0157210.1021/acs.jpca.5c01572","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c01572https://doi.org/10.1021/acs.jpca.5c01572","url":null,"abstract":"<p >Crystal growth plays a key role in product attributes and downstream processing, whereas insight into the crystal growth mechanism, especially growth unit structures and behaviors, has been limited. In this work, the growth unit structures and behaviors of 7-aminodeacetoxycephalosporanic acid were explored by experiments and molecular simulations. First, its growth units were determined as the monomer MON I and dimers connected by N₅–H₇···O₄═C₂₀ (AGG I, 1.619 Å/166 °) and N₅–H₆···O₃–C₂₀ (AGG II, 1.779 Å/174 °), using spectroscopy and molecular simulation. On the (0 0 1), (1 −1 0), and (1 1 −1) faces, MON I was preferred to diffuse from the bulk solution and adsorb over others, while on the (0 1 1) face, AGG I was favored to diffuse and adsorb. Moreover, the differences in all the growth units that diffused and attached to the crystal faces led to a specific crystal morphology.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 16","pages":"3672–3681 3672–3681"},"PeriodicalIF":2.7,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863203","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":"Correction to “Surface Formation Pathway of Nitrogen- and Sulfur-Containing Organic Compounds on Ammonium Sulfate”","authors":"Jie Chen,&nbsp;George Wandera Kisimbiri,&nbsp;Ivan Gladich,&nbsp;Nicolas Fauré,&nbsp;Erik S. Thomson,&nbsp;Robert Temperton,&nbsp;Zamin A. Kanji* and Xiangrui Kong*,&nbsp;","doi":"10.1021/acs.jpca.5c0205510.1021/acs.jpca.5c02055","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c02055https://doi.org/10.1021/acs.jpca.5c02055","url":null,"abstract":"","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 16","pages":"3762 3762"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.jpca.5c02055","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863134","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":"Research on Quantitative Analysis Method for Aluminum Alloy Using Backpropagation Artificial Neural Network Algorithm Based on LIBS Technology","authors":"Li Wang*,&nbsp;Li Xu,&nbsp;Li Li,&nbsp;Yuanxia Fu,&nbsp;Hui Gao,&nbsp;Yu Zhou and Deming Zhai,&nbsp;","doi":"10.1021/acs.jpca.5c0164510.1021/acs.jpca.5c01645","DOIUrl":"https://doi.org/10.1021/acs.jpca.5c01645https://doi.org/10.1021/acs.jpca.5c01645","url":null,"abstract":"<p >Rapid online analysis of the elemental distributions in aluminum alloys is critical for classification and quality control. This study focused on the 5052 Al–Mg alloy, utilizing laser-induced breakdown spectroscopy (LIBS) combined with a backpropagation artificial neural network (BP-ANN) to develop a quantitative model for analyzing elemental contents. Spectral data were collected from five 5052 Al–Mg alloy samples, with 188 spectra from each sample, resulting in 940 data sets. These were divided into training and test sets, with 700 data sets used for training and 225 for testing. The model predicted concentrations of Al (396.15 nm) and Mg (279.54 nm) had coefficients of determination of 0.9862 and 0.9646, root-mean-square errors of 0.6609 and 0.75005, mean absolute errors of 1.0986 and 0.5504, and mean bias errors of 0.3565 and 0.0231, respectively. These results demonstrate that the BP-ANN model, in combination with LIBS technology, provides an accurate and stable quantitative analysis method for aluminum alloys.</p>","PeriodicalId":59,"journal":{"name":"The Journal of Physical Chemistry A","volume":"129 16","pages":"3754–3761 3754–3761"},"PeriodicalIF":2.7,"publicationDate":"2025-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863135","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}