Pub Date : 2025-11-04DOI: 10.1016/j.chemphys.2025.113013
Raj Kumar Khan , B. Shivaranjini , S. Umadevi , R. Pratibha
Binary mixtures of two liquid crystals, one composed of chiral rod-like (R) and the other of achiral bent-core (BC) molecules, were investigated in order to obtain stable long range blue phases (BPs). While highly chiral BPs were found to be enhanced, the chiral nematic and chiral smectic C⁎ phases were suppressed and a long range non-chiral smectic A phase induced. Another interesting offshoot was the formation of a reentrant isotropic phase which has not been observed earlier in such systems. The results have been interpreted based on self-assembly of the R and BC molecules and the interplay of molecular chirality of the R molecules and conformation chirality of the BC molecules. The study demonstrates how phase behaviour and chirality in binary mixtures are closely connected with the specific molecular structures of the components and that a proper choice is essential for the design of new chiral materials for technological applications.
{"title":"Reentrant isotropic phase and enhanced blue phases in mixtures of chiral calamitic and achiral bent-core molecules","authors":"Raj Kumar Khan , B. Shivaranjini , S. Umadevi , R. Pratibha","doi":"10.1016/j.chemphys.2025.113013","DOIUrl":"10.1016/j.chemphys.2025.113013","url":null,"abstract":"<div><div>Binary mixtures of two liquid crystals, one composed of chiral rod-like (R) and the other of achiral bent-core (BC) molecules, were investigated in order to obtain stable long range blue phases (BPs). While highly chiral BPs were found to be enhanced, the chiral nematic and chiral smectic C<sup>⁎</sup> phases were suppressed and a long range non-chiral smectic A phase induced. Another interesting offshoot was the formation of a reentrant isotropic phase which has not been observed earlier in such systems. The results have been interpreted based on self-assembly of the R and BC molecules and the interplay of molecular chirality of the R molecules and conformation chirality of the BC molecules. The study demonstrates how phase behaviour and chirality in binary mixtures are closely connected with the specific molecular structures of the components and that a proper choice is essential for the design of new chiral materials for technological applications.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113013"},"PeriodicalIF":2.4,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-04DOI: 10.1016/j.chemphys.2025.112954
Damin Cao , Jiayi Zhao , Zhiyuan Yu , Shuo Chen
The precise manipulation of droplets takes key role in microfluidic chips, involving biological detection and chemical reactions. In the present paper, the dynamics of droplet impacting on an inclined hydrophilic-superhydrophobic surface are investigated experimentally and numerically. The processes of post-impact behaviors are captured by snapshots, suggesting that the bouncing direction can be well managed by maximal attachment distance of the droplet spreading in the hydrophilic region () and the inclined angle (). The forces between droplets and hydrophilic-superhydrophobic surface causing the unbalanced torque are studied via many-body dissipative particle dynamics (MDPD) method. Moreover, the theoretical models for predicting movement velocity and bouncing height are established through analyzing the competition between capillary force and gravity, showing good consistence to the experimental and numerical outcomes. The present work aims to provide the post-impact mechanism of droplets on heterogeneous surfaces, which is helpful to the corresponding applications.
{"title":"Dual-directional manipulation of droplet impacting on an inclined hydrophilic-superhydrophobic surface","authors":"Damin Cao , Jiayi Zhao , Zhiyuan Yu , Shuo Chen","doi":"10.1016/j.chemphys.2025.112954","DOIUrl":"10.1016/j.chemphys.2025.112954","url":null,"abstract":"<div><div>The precise manipulation of droplets takes key role in microfluidic chips, involving biological detection and chemical reactions. In the present paper, the dynamics of droplet impacting on an inclined hydrophilic-superhydrophobic surface are investigated experimentally and numerically. The processes of post-impact behaviors are captured by snapshots, suggesting that the bouncing direction can be well managed by maximal attachment distance of the droplet spreading in the hydrophilic region (<span><math><mi>e</mi></math></span>) and the inclined angle (<span><math><mi>θ</mi></math></span>). The forces between droplets and hydrophilic-superhydrophobic surface causing the unbalanced torque are studied via many-body dissipative particle dynamics (MDPD) method. Moreover, the theoretical models for predicting movement velocity and bouncing height are established through analyzing the competition between capillary force and gravity, showing good consistence to the experimental and numerical outcomes. The present work aims to provide the post-impact mechanism of droplets on heterogeneous surfaces, which is helpful to the corresponding applications.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112954"},"PeriodicalIF":2.4,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145526393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-03DOI: 10.1016/j.chemphys.2025.113014
Jincheng Ji , Simin Zhu , Changxin Li , Weihua Zhu
Density-functional tight-binding molecular dynamics simulations (DFTB-MD) were used to simulate the thermal decomposition of crystalline and nanoscale 3-nitro-1,2,4-triazole-5-one (NTO) at different temperatures. The results of MD simulations indicate that the initial decomposition mechanism of both crystalline and nanoscale NTO are dominated by the single molecule decomposition. In crystalline NTO, the rearrangement of -NO2 and direct ring opening are the dominant decomposition pathways. The C-NO2 homolysis is the main decomposition path for nanoscale NTO, and the decomposition mechanism of nanoscale NTO is significantly influenced by temperature. The activation energy for the decomposition of crystalline NTO is 15.59 kcal·mol−1, which is higher than that of 9.81 kcal·mol−1 for nanoscale NTO, indicating that the activation energy for the decomposition of nanoscale explosives is lower than that of crystalline explosives in this work. This study could provide theoretical guidance for understanding of the thermal reactions of explosives in different aggregation states.
{"title":"Exploring the differences in thermal decomposition mechanisms between crystalline and nanoscale 3-nitro-1,2,4-triazole-5-one by molecular dynamics simulations","authors":"Jincheng Ji , Simin Zhu , Changxin Li , Weihua Zhu","doi":"10.1016/j.chemphys.2025.113014","DOIUrl":"10.1016/j.chemphys.2025.113014","url":null,"abstract":"<div><div>Density-functional tight-binding molecular dynamics simulations (DFTB-MD) were used to simulate the thermal decomposition of crystalline and nanoscale 3-nitro-1,2,4-triazole-5-one (NTO) at different temperatures. The results of MD simulations indicate that the initial decomposition mechanism of both crystalline and nanoscale NTO are dominated by the single molecule decomposition. In crystalline NTO, the rearrangement of -NO<sub>2</sub> and direct ring opening are the dominant decomposition pathways. The C-NO<sub>2</sub> homolysis is the main decomposition path for nanoscale NTO, and the decomposition mechanism of nanoscale NTO is significantly influenced by temperature. The activation energy for the decomposition of crystalline NTO is 15.59 kcal·mol<sup>−1</sup>, which is higher than that of 9.81 kcal·mol<sup>−1</sup> for nanoscale NTO, indicating that the activation energy for the decomposition of nanoscale explosives is lower than that of crystalline explosives in this work. This study could provide theoretical guidance for understanding of the thermal reactions of explosives in different aggregation states.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113014"},"PeriodicalIF":2.4,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study employs density functional theory (DFT) to unravel the proton -coupled resonance mechanism underlying the isomerization of ethyl 4-chloro-2-methoxyiminoacetoacetate (TBM), a key intermediate in the synthesis of third-generation cephalosporin antibiotics. DFT calculations at the M06-2×/6–311++G(d,p) level reveal that acid-catalyzed protonation significantly reduces the isomerization barrier (ΔΔG = 2.914 kJ/mol). This remarkable decrease is attributed to the formation of 3-center-4-electron hydrogen bonding and π-electron redistribution, which stabilize the transition state by avoiding diradical formation. The protonation-induced charge transfer is further shown to enhance resonance stabilization within the conjugated O=C-C=N-O framework, leading to a more flexible and less polarized molecular configuration. To generalize the insights derived from the TBM system, we incorporate machine learning (ML) models that integrate quantum chemical descriptors and global molecular properties. The ML analysis, particularly using XGBoost (R2 = 0.927, RMSE = 4.765 kJ/mol), successfully identifies the key physicochemical features governing the isomerization barrier. SHAP-based feature importance analysis demonstrates that protonation-induced charge redistribution on oxygen atoms is the most significant contributor to resonance stabilization, confirming the mechanism proposed by DFT. These findings establish a general correlation between protonation-driven electronic effects and isomerization feasibility in conjugated systems, offering a predictive framework for the rational design of acid-catalyzed transformations in pharmaceutical chemistry.
{"title":"Machine learning and DFT elucidation of proton-coupled resonance mechanisms in acid-catalyzed ethyl 4-chloro-2-methoxyiminoacetoacetate isomerization","authors":"Yuqing Zhang , Xianqiang Meng , Jing Chen , Jingtao Wang","doi":"10.1016/j.chemphys.2025.112996","DOIUrl":"10.1016/j.chemphys.2025.112996","url":null,"abstract":"<div><div>This study employs density functional theory (DFT) to unravel the proton -coupled resonance mechanism underlying the isomerization of ethyl 4-chloro-2-methoxyiminoacetoacetate (TBM), a key intermediate in the synthesis of third-generation cephalosporin antibiotics. DFT calculations at the M06-2×/6–311++G(d,p) level reveal that acid-catalyzed protonation significantly reduces the isomerization barrier (ΔΔG = 2.914 kJ/mol). This remarkable decrease is attributed to the formation of 3-center-4-electron hydrogen bonding and π-electron redistribution, which stabilize the transition state by avoiding diradical formation. The protonation-induced charge transfer is further shown to enhance resonance stabilization within the conjugated O=C-C=N-O framework, leading to a more flexible and less polarized molecular configuration. To generalize the insights derived from the TBM system, we incorporate machine learning (ML) models that integrate quantum chemical descriptors and global molecular properties. The ML analysis, particularly using XGBoost (R<sup>2</sup> = 0.927, RMSE = 4.765 kJ/mol), successfully identifies the key physicochemical features governing the isomerization barrier. SHAP-based feature importance analysis demonstrates that protonation-induced charge redistribution on oxygen atoms is the most significant contributor to resonance stabilization, confirming the mechanism proposed by DFT. These findings establish a general correlation between protonation-driven electronic effects and isomerization feasibility in conjugated systems, offering a predictive framework for the rational design of acid-catalyzed transformations in pharmaceutical chemistry.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112996"},"PeriodicalIF":2.4,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-02DOI: 10.1016/j.chemphys.2025.113012
Xiong Zhang , Pengju Li , Bin Liu , Fuchun Zhang
This study investigates the regulation of optoelectronic properties in γ-graphyne/Janus MoSSe heterojunctions via first-principles calculations and molecular dynamics simulations. A systematic investigation of six distinct stacking configurations confirms that all resulting heterojunctions are thermodynamically stable and exhibit the characteristics of stable, indirect bandgap semiconductors with type-II band alignment. Significant optical absorption occurs within the infrared-visible region, demonstrating superior absorption performance along the zz direction compared to monolayer graphyne (GY). The extent of charge transfer correlates systematically with the stacking configuration, wherein electrons consistently migrate from the GY layer to the MoSSe layer. Non-equilibrium Green's function calculations for the most stable type-b stacking indicate that the current-voltage characteristics exhibit higher current in the zz orientation than in the ac orientation. These results demonstrate the suitability of this heterojunction for high-speed photodetectors and its significant application potential within the optoelectronic field.
{"title":"Stacking-modulated optoelectronics and Electron transport in γ-Graphyne/Janus MoSSe Heterostructures: A first-principles study","authors":"Xiong Zhang , Pengju Li , Bin Liu , Fuchun Zhang","doi":"10.1016/j.chemphys.2025.113012","DOIUrl":"10.1016/j.chemphys.2025.113012","url":null,"abstract":"<div><div>This study investigates the regulation of optoelectronic properties in γ-graphyne/Janus MoSSe heterojunctions via first-principles calculations and molecular dynamics simulations. A systematic investigation of six distinct stacking configurations confirms that all resulting heterojunctions are thermodynamically stable and exhibit the characteristics of stable, indirect bandgap semiconductors with type-II band alignment. Significant optical absorption occurs within the infrared-visible region, demonstrating superior absorption performance along the zz direction compared to monolayer graphyne (GY). The extent of charge transfer correlates systematically with the stacking configuration, wherein electrons consistently migrate from the GY layer to the MoSSe layer. Non-equilibrium Green's function calculations for the most stable type-b stacking indicate that the current-voltage characteristics exhibit higher current in the zz orientation than in the ac orientation. These results demonstrate the suitability of this heterojunction for high-speed photodetectors and its significant application potential within the optoelectronic field.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113012"},"PeriodicalIF":2.4,"publicationDate":"2025-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-02DOI: 10.1016/j.chemphys.2025.113011
Ghulam Nabi , Uzair Ahmed , Wajid Ali , Zaheer Ahmad , Khudija Munir , Muhammad Hamayun , Faiza Naseem , Khuram Shahzad Ahmad , Essam A. Al-Ammar
Utilization of hydrofluoric acid (HF) for exfoliation of MXenes by etching is common but its toxic and corrosive nature is an immense hindrance. Here, a facile hydrothermal approach that avoid direct use of HF has been reported, which successfully exfoliates the Max phase of Nb2AlC into multilayered Nb2CTx having an increased c-LP = 24.86 Å. The structure, morphology, surface composition and surface chemistry has been determined by using XRD, FTIR, SEM, EDX, TEM while CV, GCD and EIS techniques were used to determine the electrochemical behavior of the material. Nb2CTx shows tremendous specific capacitance (Cs) of 345 Fg−1 @ 1 Ag−1 with excellent 85 % retention after 10,000 cycles having low Rct. Dunn plot exhibited nearly 70 % capacitive nature at 5 mVs−1 with increasing behaviors and power law exhibits the pseudo capacitive nature as b = 0.79. So, using this relatively non-hazardous approach, multi-layer Nb2CTx MXene could be produced effectively by avoiding direct use of HF. Owing to highly pseudo capacitive nature, excellent specific capacitance (Cs), low charge transfer resistance (Rct) and high stability this material could be utilized as pseudocapacitor electrode for next generation high-tech energy storage applications.
{"title":"Non-violent in-situ HF based exfoliation approach for 2D Nb2CTx MXene as promising pseudocapacitor electrode applications","authors":"Ghulam Nabi , Uzair Ahmed , Wajid Ali , Zaheer Ahmad , Khudija Munir , Muhammad Hamayun , Faiza Naseem , Khuram Shahzad Ahmad , Essam A. Al-Ammar","doi":"10.1016/j.chemphys.2025.113011","DOIUrl":"10.1016/j.chemphys.2025.113011","url":null,"abstract":"<div><div>Utilization of hydrofluoric acid (HF) for exfoliation of MXenes by etching is common but its toxic and corrosive nature is an immense hindrance. Here, a facile hydrothermal approach that avoid direct use of HF has been reported, which successfully exfoliates the Max phase of Nb<sub>2</sub>AlC into multilayered Nb<sub>2</sub>CT<sub>x</sub> having an increased c-LP = 24.86 Å. The structure, morphology, surface composition and surface chemistry has been determined by using XRD, FTIR, SEM, EDX, TEM while CV, GCD and EIS techniques were used to determine the electrochemical behavior of the material. Nb<sub>2</sub>CT<sub>x</sub> shows tremendous specific capacitance (C<sub>s</sub>) of 345 Fg<sup>−1</sup> @ 1 Ag<sup>−1</sup> with excellent 85 % retention after 10,000 cycles having low R<sub>ct</sub>. Dunn plot exhibited nearly 70 % capacitive nature at 5 mVs<sup>−1</sup> with increasing behaviors and power law exhibits the pseudo capacitive nature as b = 0.79. So, using this relatively non-hazardous approach, multi-layer Nb<sub>2</sub>CT<sub>x</sub> MXene could be produced effectively by avoiding direct use of HF. Owing to highly pseudo capacitive nature, excellent specific capacitance (C<sub>s</sub>), low charge transfer resistance (R<sub>ct</sub>) and high stability this material could be utilized as pseudocapacitor electrode for next generation high-tech energy storage applications.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113011"},"PeriodicalIF":2.4,"publicationDate":"2025-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-01DOI: 10.1016/j.chemphys.2025.112995
Xiujuan Zhang, Wentao Li
Dynamics studies were performed on the Sr+(4d2D) + H2(v = 0, 1; j = 0) reaction based on diabatic potential energy surfaces. The results demonstrate that the reaction pathway Sr+(4d2D) + H2 is the primary mechanism for SrH+ formation, exhibiting significantly higher reactivity compared to the Sr+(5s2S) + H2 reaction. Calculated dynamical properties including reaction probabilities, integral cross sections, and differential cross sections for SrH+ formation, reveal that vibrational excitation of the H2 reactant substantially enhances reactivity. Furthermore, the differential cross sections are predominantly forward-scattered, indicating that the abstraction mechanism dominates the reaction.
{"title":"Nonadiabatic dynamics study of the Sr+(4d2D) + H2(v = 0, 1; j = 0) reaction","authors":"Xiujuan Zhang, Wentao Li","doi":"10.1016/j.chemphys.2025.112995","DOIUrl":"10.1016/j.chemphys.2025.112995","url":null,"abstract":"<div><div>Dynamics studies were performed on the Sr<sup>+</sup>(4d<sup>2</sup>D) + H<sub>2</sub>(<em>v</em> = 0, 1; <em>j</em> = 0) reaction based on diabatic potential energy surfaces. The results demonstrate that the reaction pathway Sr<sup>+</sup>(4d<sup>2</sup>D) + H<sub>2</sub> is the primary mechanism for SrH<sup>+</sup> formation, exhibiting significantly higher reactivity compared to the Sr<sup>+</sup>(5s<sup>2</sup>S) + H<sub>2</sub> reaction. Calculated dynamical properties including reaction probabilities, integral cross sections, and differential cross sections for SrH<sup>+</sup> formation, reveal that vibrational excitation of the H<sub>2</sub> reactant substantially enhances reactivity. Furthermore, the differential cross sections are predominantly forward-scattered, indicating that the abstraction mechanism dominates the reaction.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112995"},"PeriodicalIF":2.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Understanding the effects of different environments and alkali metal substitution on the excited-state intramolecular proton transfer (ESIPT) process and emission mechanisms of luminescent materials is crucial for the design of next-generation solid-state emitters. In this study, the photophysical properties of three alkali-metal-substituted salicylidene diamine derivatives, GS-Li, GS-Na, and GS-K, were systematically investigated in methanol solution and in the solid, based on density functional theory (DFT) and quantum mechanics/molecular mechanics (QM/MM) approaches. In methanol, all three compounds exhibit barrierless ESIPT processes accompanied by twisted intramolecular charge transfer (TICT), resulting in fluorescence quenching. In the solid state, the crystal structure of GS-K exhibits characteristics resembling a hybrid of GS-Li and GS-Na. Therefore, our discussion focuses primarily on GS-Li and GS-Na, both of which display pronounced aggregation-induced emission (AIE) properties. GS-Li exhibits strong K* fluorescence emission through a barrierless ESIPT process coupled with an intramolecular charge transfer (ICT) mechanism. GS-Na undergoes barrierless ground-state intramolecular proton transfer (GSIPT) and exhibits K* fluorescence in the excited state. This work provides a comprehensive understanding of the ESIPT mechanisms and emission behaviors of these derivatives. It reveals the interplay among TICT, ICT, and ESIPT processes under different environments, offering valuable insights for the design and development of highly efficient luminescent materials with combined ESIPT and AIE characteristics.
{"title":"Elucidating the activation mechanism of ESIPT dark state in Salicylidene Glycine Schiff bases via liquid–solid phase switching","authors":"Tianyu Cui, Siqi Wang, Xiaonan Wang, Yifu Zhang, Hui Li, Jixing Cai","doi":"10.1016/j.chemphys.2025.112981","DOIUrl":"10.1016/j.chemphys.2025.112981","url":null,"abstract":"<div><div>Understanding the effects of different environments and alkali metal substitution on the excited-state intramolecular proton transfer (ESIPT) process and emission mechanisms of luminescent materials is crucial for the design of next-generation solid-state emitters. In this study, the photophysical properties of three alkali-metal-substituted salicylidene diamine derivatives, GS-Li, GS-Na, and GS-K, were systematically investigated in methanol solution and in the solid, based on density functional theory (DFT) and quantum mechanics/molecular mechanics (QM/MM) approaches. In methanol, all three compounds exhibit barrierless ESIPT processes accompanied by twisted intramolecular charge transfer (TICT), resulting in fluorescence quenching. In the solid state, the crystal structure of GS-K exhibits characteristics resembling a hybrid of GS-Li and GS-Na. Therefore, our discussion focuses primarily on GS-Li and GS-Na, both of which display pronounced aggregation-induced emission (AIE) properties. GS-Li exhibits strong K* fluorescence emission through a barrierless ESIPT process coupled with an intramolecular charge transfer (ICT) mechanism. GS-Na undergoes barrierless ground-state intramolecular proton transfer (GSIPT) and exhibits K* fluorescence in the excited state. This work provides a comprehensive understanding of the ESIPT mechanisms and emission behaviors of these derivatives. It reveals the interplay among TICT, ICT, and ESIPT processes under different environments, offering valuable insights for the design and development of highly efficient luminescent materials with combined ESIPT and AIE characteristics.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112981"},"PeriodicalIF":2.4,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, how to enhance the effect of field-free orientation has attracted the attention of many researchers. Here, we propose a scheme for generating field-free orientation of LiH molecules using a train of few-cycle/single-cycle terahertz pulses. Theoretical calculations indicate that the field-free orientation degree of LiH molecules gradually increases with the number of laser pulses. After the interaction with five terahertz laser pulses, the maximum field-free orientation degree of molecules reaches 0.8568. Under this condition, the duration during which the field-free orientation degree remains above 0.5 is 161.8 fs, which is sufficient for experimental utilization. When the temperature is below 20 K, the molecules orientation degree remains above 0.5. By sequentially discussing the relationship between the time delay of adjacent pulses and the rotational state population, we uncovered the control mechanism of the proposed scheme. Additionally, we examined the laser-pulse-induced changes in their angular distribution.
{"title":"Field-free orientation of LiH molecules controlled by a train of few-cycle/single-cycle terahertz laser pulses","authors":"Yuemin Leng, Wenqian Li, Yaoyao Wei, Shou Chai, Gaoren Wang, Yongchang Han, Jie Yu","doi":"10.1016/j.chemphys.2025.113003","DOIUrl":"10.1016/j.chemphys.2025.113003","url":null,"abstract":"<div><div>In recent years, how to enhance the effect of field-free orientation has attracted the attention of many researchers. Here, we propose a scheme for generating field-free orientation of LiH molecules using a train of few-cycle/single-cycle terahertz pulses. Theoretical calculations indicate that the field-free orientation degree of LiH molecules gradually increases with the number of laser pulses. After the interaction with five terahertz laser pulses, the maximum field-free orientation degree of molecules reaches 0.8568. Under this condition, the duration during which the field-free orientation degree remains above 0.5 is 161.8 fs, which is sufficient for experimental utilization. When the temperature is below 20 K, the molecules orientation degree remains above 0.5. By sequentially discussing the relationship between the time delay of adjacent pulses and the rotational state population, we uncovered the control mechanism of the proposed scheme. Additionally, we examined the laser-pulse-induced changes in their angular distribution.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 113003"},"PeriodicalIF":2.4,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-30DOI: 10.1016/j.chemphys.2025.112999
Qiuhui Zhao , Yaqi Jing , Jiale Zhang , Jiadan Xue , Jianjun Liu , Jianyuan Qin , Zhi Hong , Yong Du
Isoniazid (INH), a frontline anti-tuberculosis drug, faces rising resistance and hepatotoxicity, motivating crystal-engineering approaches. The INH-4-hydroxybenzoic acid (INH-HBA) cocrystal shows multiple polymorphs, its hydrate exists in two forms whose lattice water markedly alters hydrogen-bond topology and molecular packing. We combined terahertz time-domain spectroscopy (THz-TDS) and FT-Raman spectroscopy with periodic solid-state DFT and potential energy distribution (PED) analysis to assign vibrational modes and link spectral features to structural motifs. Hirshfeld surface analysis indicates form I is dominated by multi-directional OH...N contacts and an NH...O synthon that yields parallel layered packing. By contrast, form II uses lattice water to bridge OH...O/NH...O interactions and weak CH...O contacts, producing a cross-stacked three-dimensional network lacking dimers. Observed spectral differences are attributed to these distinct intermolecular interactions and associated vibrations. By integrating experimental and theoretical data, this study provides spectroscopic-structural insights into INH-HBA hydrate polymorphism, offering a foundation for pharmaceutical cocrystal identification and design.
{"title":"Polymorphic behavior in isoniazid-4-hydroxybenzoic acid hydrated cocrystals: A combined terahertz, Raman vibrational spectroscopy, and DFT analysis","authors":"Qiuhui Zhao , Yaqi Jing , Jiale Zhang , Jiadan Xue , Jianjun Liu , Jianyuan Qin , Zhi Hong , Yong Du","doi":"10.1016/j.chemphys.2025.112999","DOIUrl":"10.1016/j.chemphys.2025.112999","url":null,"abstract":"<div><div>Isoniazid (INH), a frontline anti-tuberculosis drug, faces rising resistance and hepatotoxicity, motivating crystal-engineering approaches. The INH-4-hydroxybenzoic acid (INH-HBA) cocrystal shows multiple polymorphs, its hydrate exists in two forms whose lattice water markedly alters hydrogen-bond topology and molecular packing. We combined terahertz time-domain spectroscopy (THz-TDS) and FT-Raman spectroscopy with periodic solid-state DFT and potential energy distribution (PED) analysis to assign vibrational modes and link spectral features to structural motifs. Hirshfeld surface analysis indicates form I is dominated by multi-directional O<img>H...N contacts and an <span><math><mrow><msubsup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mrow><mo>(</mo><mn>8</mn><mo>)</mo></mrow></mrow></math></span> N<img>H...O synthon that yields parallel layered packing. By contrast, form II uses lattice water to bridge O<img>H...O/N<img>H...O interactions and weak C<img>H...O contacts, producing a cross-stacked three-dimensional network lacking <span><math><mrow><msubsup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mrow><mo>(</mo><mn>8</mn><mo>)</mo></mrow></mrow></math></span> dimers. Observed spectral differences are attributed to these distinct intermolecular interactions and associated vibrations. By integrating experimental and theoretical data, this study provides spectroscopic-structural insights into INH-HBA hydrate polymorphism, offering a foundation for pharmaceutical cocrystal identification and design.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"602 ","pages":"Article 112999"},"PeriodicalIF":2.4,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145474614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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