Rasmus Lavén,Erik Fransson,Paul Erhart,Fanni Juranyi,Garrett E Granroth,Maths Karlsson
{"title":"Unraveling the Nature of Vibrational Dynamics in CsPbI3 by Inelastic Neutron Scattering and Molecular Dynamics Simulations.","authors":"Rasmus Lavén,Erik Fransson,Paul Erhart,Fanni Juranyi,Garrett E Granroth,Maths Karlsson","doi":"10.1021/acs.jpclett.5c00778","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c00778","url":null,"abstract":"Cesium lead iodide, CsPbI3, is an optoelectronic material of large interest for various technological applications; however, fundamental questions surrounding the vibrational dynamics of this material, especially regarding its role in structural phase transitions, remain to be elucidated. Here, in a combined variable temperature inelastic neutron scattering (INS) and machine-learning based molecular dynamics (MD) simulation study, we show that the stable phase at room temperature, i.e., the nonperovskite δ-phase, exhibits phonon modes with weak anharmonicity with only a weak temperature dependence from 10 K all the way up to the transition to the cubic perovskite α-phase at approximately 600 K. In contrast, the α-phase features anharmonic and damped vibrational dynamics, mainly associated with overdamped tilting motions of the PbI6 octahedra. Crucially, these overdamped tilting modes, which relate to the tetragonal and orthorhombic distorted perovskite phases (β- and γ-phase, respectively) formed at lower temperatures, stay overdamped by more than 100 K above the respective phase transition. This suggests a flat energy landscape of octahedral tilting motions in α-CsPbI3 and with structural fluctuations on the picosecond time scale with tilting patterns that locally resemble the structure of the β- and γ-phases. The vibrational dynamics of α-CsPbI3 are also characterized by pronounced anharmonic motions with large thermal displacements of the Cs+ ions, but these modes remain underdamped at 600 K.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"68 1","pages":"4812-4818"},"PeriodicalIF":6.475,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143921076","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}
Thilo Bissbort, Kai-Uwe Hess, Daniel Weidendorfer, Elena V. Sturm, Jürgen E. K. Schawe, Martin Wilding, Bettina Purgstaller, Katja E. Goetschl, Sebastian Sturm, Knut Müller-Caspary, Wolfgang Schmahl, Erika Griesshaber, Martin Dietzel, Donald B. Dingwell
{"title":"Dehydration-Driven Glass Formation in Aqueous Carbonates","authors":"Thilo Bissbort, Kai-Uwe Hess, Daniel Weidendorfer, Elena V. Sturm, Jürgen E. K. Schawe, Martin Wilding, Bettina Purgstaller, Katja E. Goetschl, Sebastian Sturm, Knut Müller-Caspary, Wolfgang Schmahl, Erika Griesshaber, Martin Dietzel, Donald B. Dingwell","doi":"10.1021/acs.jpclett.5c00551","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c00551","url":null,"abstract":"Amorphous carbonates, in their liquid and solid (glassy) forms, have been identified to play important roles in biomineralization, volcanism, and deep element cycling. Anhydrous amorphous calcium and calcium–magnesium carbonate (ACC and ACMC05, respectively) are structural glasses that exhibit a glass transition upon being heated. We report a significant effect of the water content on glass formation. The results yield a parametrization enabling prediction of the stability of their liquid and solid amorphous phases as a function of temperature and water content. These results, obtained through novel fast differential scanning calorimetry, demonstrate that hydrous ACC and ACMC05 do indeed exhibit the behavior of structural glasses and that dehydration of these materials by lyophilization is a route that can be used to isothermally cross the glass transition. This work presents a viable process for a significantly wider range of geo- and biomaterials. Dehydration-controlled formation of glassy ACC therefore constitutes the missing link in the transformation from supersaturated aqueous solutions through an intermediate amorphous glassy state to crystalline CaCO<sub>3</sub> polymorphs. These results yield direct implications for the mechanistic interpretation of geological processes and biomineralization.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"3 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143915983","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":"Bridging Dimensionality Reduction and Stochastic Sampling: The DA2-MC Algorithm for Protein Dynamics.","authors":"Ruizhe Shen,Qiang Zhu,Limu Hu,Jing Ma,Wei Wang,Hao Dong","doi":"10.1021/acs.jpclett.5c00921","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c00921","url":null,"abstract":"Elucidating protein dynamics and conformational changes is crucial for understanding their biological functions. This work introduces a data-driven accelerated conformational searching algorithm incorporating a Monte Carlo strategy, termed the DA2-MC method, which integrates dimensionality reduction techniques with Monte Carlo strategies to efficiently explore unknown protein conformations. The DA2-MC method was applied to investigate the folding mechanisms of two miniproteins, chignolin and WW domain, revealing their dynamic behavior in different conformational states at a reasonable computational cost. A Markov state model-based analysis of chignolin's folding pathway corroborated the dynamic insights obtained from the DA2-MC method. Moreover, free energy calculations initiated with the intermediate structures identified by DA2-MC yielded results consistent with published literature, affirming the method's reliability in accelerating conformational searches and reconstructing equilibrium properties. Collectively, the DA2-MC method emerges as an effective tool for efficiently exploring protein conformations, facilitating the identification of potential functional conformations on complex energy landscapes.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"117 1","pages":"4788-4795"},"PeriodicalIF":6.475,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143921079","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":"Photogenerated Carriers Surviving for Milliseconds in Perovskites under the Protection of Shallow Trap States.","authors":"Hao-Yi Wang,Xinli Wang,Jie Gao,Jiyuan Wu,Yi Wang,Li-Min Fu,Xi-Cheng Ai,Jian-Ping Zhang","doi":"10.1021/acs.jpclett.5c00901","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c00901","url":null,"abstract":"The performance of perovskite-based photovoltaic and light-emitting devices is susceptive to the interaction between charge carriers and trap states. The inherent trap state tolerance endows perovskite with a series of unprecedented properties; however, the underlying mechanisms remain poorly explored. Herein, we show, with a novel time-resolved stimulated emission spectroscopy approach, that photogenerated carriers are effectively prevented from internal nonradiative recombination and external luminescence quenching by shallow trap states. The photogenerated carriers survive for a period of >3 ms, 4 orders of magnitude longer than the submicrosecond photoluminescence lifetime. The surprisingly long-lived charge carriers can be quantitatively accounted for by a proposed model of trap state-assisted carrier protection (TSACP), which is consolidated by the results of confirmatory experiments on perovskites with varying chemical compositions and micronano structures. These findings shed light on the mechanism of carrier-trap state interaction, which will benefit for more effective defect engineering of perovskite materials and devices.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"47 1","pages":"4748-4753"},"PeriodicalIF":6.475,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143914975","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 “The Melamine-Driven Solvation Effect Promotes Oxygen Reduction on Platinum Catalyst: Machine Learning-Aided Free Energy Calculations”","authors":"Ryosuke Jinnouchi, Saori Minami","doi":"10.1021/acs.jpclett.5c01222","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c01222","url":null,"abstract":"In our original manuscript, we inadvertently used base-10 logarithms instead of natural logarithms in implementing eqs (S32) and (S33) of the Supporting Information, which are used to calculate the vibrational quantum correction for the hydrogen atom bonded to water. This error resulted in an overestimation of the free energy of the hydrogen atom by approximately 60 meV, thereby lowering the redox potential <i>U</i><sub>OH</sub> associated with OH adsorption on Pt catalysts both with and without melamine, as well as on various Pt alloys by 60 mV, shown in Figure 3 (a). A corrected version of Figure 3 (a), along with updated vibrational quantum correction values in Table S3 of the Supporting Information, is provided below. Since the evaluation of catalytic activity in our study relied on relative differences in <i>U</i><sub>OH</sub> among the Pt catalysts, this uniform shift in absolute values does not alter the other results presented. Consequently, the main conclusions of the study remain unaffected. Nonetheless, the corrected absolute value of <i>U</i><sub>OH</sub>, for instance, on Pt(111) increases from 0.40 to 0.46 V vs SHE, bringing it closer to the experimental reference value of 0.6 V vs SHE in ref. [14] of the original manuscript. Figure 3. (a) Redox potentials versus SHE for reaction 5 on Pt(111), Pt(111) with melamine, Pt/Pt<sub>2</sub>Cu/Pt(111), Pt/PtCu<sub>2</sub>/Pt(111), and Pt/Cu/Pt(111) surfaces obtained from TI calculations. The units of free energy and vibrational frequencies are eV and cm<sup>–1</sup>, respectively. Corrected values are indicated in bold. This article has not yet been cited by other publications.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"14 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143915986","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}
Pengfei Zhang, Shuwei Tang, Da Wan, Peng Ai, Tuo Zheng, Tengyue Yan, Yujie Bao, Yufei Meng, Shulin Bai
{"title":"Janus Effect of Phonons in Inducing Diffusons in Nanolayered XMg2Bi2 (X = Sr, Ba): Static–Dynamic Transition for Cations","authors":"Pengfei Zhang, Shuwei Tang, Da Wan, Peng Ai, Tuo Zheng, Tengyue Yan, Yujie Bao, Yufei Meng, Shulin Bai","doi":"10.1021/acs.jpclett.5c00916","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c00916","url":null,"abstract":"The thermoelectric performance of XMg<sub>2</sub>Bi<sub>2</sub> (X = Sr, Ba) materials is systematically investigated through integrated first-principles calculations, Boltzmann transport theory, and a two-channel model in this work. The temperature-activated static–dynamic transition in X (X = Sr, Ba) atoms vibrations induces a Janus effect of phonons, facilitating dual phonon transport regimes characterized by normal phonon and diffusons. The comparable ionicity between X<sup>2+</sup> (X = Sr, Ba) and [Mg<sub>2</sub>Bi<sub>2</sub>]<sup>2–</sup> layers disrupts the conventional Zintl-phase characteristics, leading to an atypically isotropic lattice thermal conductivity within their materials. Concurrently, charge-insulating X<sup>2+</sup> (X = Sr, Ba) layers restrict out-of-plane carrier mobility, creating a distinctive two-dimensional (2D) electronic transport framework superimposed on three-dimensional (3D) phonon dynamics. By disentanglement of the cross-dimensional transport phenomena through a two-channel model and multicarrier scattering analysis, the XMg<sub>2</sub>Bi<sub>2</sub> (X = Sr, Ba) materials achieve remarkable thermoelectric performance with the optimal figure of merits (<i>ZT</i><sub>max</sub>) of 1.5 (<i>p</i>-type) and 1.9 (<i>n</i>-type) at 600 K, respectively.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"19 1","pages":""},"PeriodicalIF":6.475,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143910808","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}
Bashir Sbaiti, Jonathan D. Schultz, Kelsey A. Parker, David N. Beratan
{"title":"Machine Learning for Video Classification Enables Quantifying Intermolecular Couplings from Simulated Time-Evolved Multidimensional Spectra","authors":"Bashir Sbaiti, Jonathan D. Schultz, Kelsey A. Parker, David N. Beratan","doi":"10.1021/acs.jpclett.5c00588","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c00588","url":null,"abstract":"Signals in two-dimensional electronic spectroscopy (2DES) encode information about electronic, vibrational, and vibronic couplings in molecular structures. However, chemical information is often difficult to extract. Here, we use a (2+1)-dimensional convolutional neural network ((2+1)D-CNN) to map simulated 2DES spectra to their underlying electronic couplings. The (2+1)D-CNN approach, in contrast to lower-dimensional network architectures, can access all of the time and frequency dimensions in the 2DES signal. We find that the (2+1)D-CNN algorithm classifies regimes of Coulombic couplings in dimers with a 10-fold cross-validation accuracy of (96.2 ± 1.0)%. By examining the optimized filters within the CNN, we find that the (2+1)D-CNN learns from frequency-domain peaks in 2DES spectra and their time evolution (including quantum beating). We also generate and analyze class-activation maps (CAMs) to reveal which features of the spectroscopic data are most important for the (2+1)D-CNN classifications. These studies provide an ML approach to address inverse problems in multidimensional spectroscopy and provide strategies to better understand how chemical information is encoded in spectroscopic data.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"56 1","pages":"4707-4714"},"PeriodicalIF":6.475,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143910430","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}
Yeonsig Nam, Majed Chergui, Linda Young, Jérémy R. Rouxel
{"title":"Linear and Nonlinear X-ray Spectra of Chiral Molecules: X-ray Circular Dichroism, Sum- and Difference-Frequency Generation of Fenchone and Cysteine","authors":"Yeonsig Nam, Majed Chergui, Linda Young, Jérémy R. Rouxel","doi":"10.1021/acs.jpclett.5c00389","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c00389","url":null,"abstract":"Recent advancements in X-ray light sources enable element-sensitive nonlinear spectroscopies for probing molecular chirality. We simulate X-ray absorption spectroscopy, X-ray circular dichroism (XCD), and nonlinear optical/X-ray SFG and DFG (OX SFG/DFG) signals for two prototypical chiral molecules, fenchone and cysteine. Our multireference simulations reproduce experimental data and reveal how novel X-ray spectroscopies exploit the site- and element-sensitivity of X-rays to uncover molecular asymmetry. The XCD spectra show strong asymmetries at chiral centers, while distant atoms contribute weaker signals. The OX SFG/DFG signals, under fixed resonant optical excitation, strongly depend on the core and valence excitations. This allows us to introduce two-dimensional (2D) chirality-sensitive valence-core spectroscopy, which provides insight into the overlap between valence orbitals and local molecular asymmetry. Finally, our estimates using realistic laser and X-ray pulse parameters demonstrate that such nonlinear experiments are feasible at XFELs, offering a promising tool for investigating chiral molecules.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"99 1","pages":"4652-4661"},"PeriodicalIF":6.475,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143910570","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":"MXene-Mediated Electronic State Engineering of Nickel Hydroxide for Efficient Piezo-Catalytic Hydrogen Peroxide Synthesis","authors":"Yuxiu Sun, Jiahao Liu, Zhaorui Zhang, Chenshuai Han, Weiliang Qi, Jinkui Chu, Siqi Liu, Minghui Yang","doi":"10.1021/acs.jpclett.5c00685","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c00685","url":null,"abstract":"The piezo-catalytic synthesis of hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) offers a sustainable alternative to the traditional anthraquinone process by enhancing both the water oxidation reaction (WOR) and oxygen reduction reaction (ORR). However, conventional high-dielectric-constant piezoelectric materials, despite their superior piezoelectric responses, generally feature wide band gaps, low electrical conductivity, and a limited number of active sites─catalytically unfavorable characteristics that restrict their piezocatalytic efficiency. To address this, we developed a 2D Ni(OH)<sub>2</sub>-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene composite for efficient H<sub>2</sub>O<sub>2</sub> production in pure water. The Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> MXene modifies the electronic states of Ni(OH)<sub>2</sub>, enhancing its deprotonation ability (Ni<sup>2+</sup> to Ni<sup>3+</sup>) and creating hypervalent nickel active sites that boost H<sub>2</sub>O<sub>2</sub> synthesis. Theoretical and experimental studies confirm that H<sub>2</sub>O<sub>2</sub> generation occurs through combined WOR and ORR pathways, with ORR being dominant. The hierarchical 2D nanosheet structure facilitates crystal deformation under mechanical stress, amplifying the piezoelectric effect and reducing the energy input required for redox reactions. As a result, the Ni(OH)<sub>2</sub>-Ti<sub>3</sub>C<sub>2</sub>T<sub><i>x</i></sub> composite achieves an impressive H<sub>2</sub>O<sub>2</sub> yield of 351.1 μmol·g<sup>–1</sup>·h<sup>–1</sup>. This work provides a novel design strategy for high-performance piezo-catalysts in sustainable H<sub>2</sub>O<sub>2</sub> production.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"15 1","pages":"4724-4733"},"PeriodicalIF":6.475,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143910572","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":"Machine Learning Surrogate Models for Mechanistic Kinetics: Embedding Atom Balance and Positivity","authors":"Tim Kircher, Martin Votsmeier","doi":"10.1021/acs.jpclett.5c00602","DOIUrl":"https://doi.org/10.1021/acs.jpclett.5c00602","url":null,"abstract":"Multiscale simulations of reactive flows are critical in many fields. However, their application is often hindered by the high computational cost of solving detailed chemical kinetics. Recent advances in surrogate models for reactive chemistry offer promising speedups, but ensuring physical consistency remains challenging. In particular, machine learning models for chemical kinetics must enforce atom balance and guarantee the positivity of predicted concentrations. Here, we introduce a positivity preserving projection and a correction by linear interpolation backtracking which simultaneously guarantee both constraints. We demonstrate this using two practical examples from atmospheric chemistry and heterogeneous catalysis, as well as for a large number of random, synthetically generated reaction systems. In all cases, our approach yields exclusively positive model predictions conforming to the atom balance, without reducing the overall accuracy of the model.","PeriodicalId":62,"journal":{"name":"The Journal of Physical Chemistry Letters","volume":"20 1","pages":"4715-4723"},"PeriodicalIF":6.475,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143910571","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}