Himanshu Kumar Vishwakarma, and , Amalendu Chandra*,
{"title":"MgCl2水溶液的太赫兹和介电光谱:使用极化模型的永久偶极子和诱导偶极子的自相关和互相关贡献。","authors":"Himanshu Kumar Vishwakarma, and , Amalendu Chandra*, ","doi":"10.1021/acs.jpcb.5c02574","DOIUrl":null,"url":null,"abstract":"<p >We have investigated the terahertz (THz) and dielectric spectra of aqueous MgCl<sub>2</sub> solutions through molecular dynamics simulations using the AMOEBA polarizable force field for both water and ions. We calculated the differenceabsorption spectra for three different concentrations of MgCl<sub>2</sub> by subtracting the pure water contribution from the total absorption spectra of the solutions. The difference THz spectra of the solutions are divided into ion–ion, water–water, and ion–water components, with further resolution into self- and cross-correlations. Through these dissections, we gained insights into spectral features arising from ion–ion and ion–water correlations and also from changes in water–water correlations caused by ions. The contributions of permanent and induced dipole auto- and cross-correlations provide further insights into the nature of low-frequency vibrational modes involving cation–water and anion–water interactions. Our results reveal that the hydrogen bond stretch motion of water is suppressed by ions, whereas an additional contribution comes from the chloride ion–water hydrogen bond stretch motion. The low-frequency modes in the ion–water part are found to be mainly dominated by cation–water interactions. Furthermore, the results of the low-frequency dielectric spectra show that the relaxation of the collective dipole of water is slowed significantly in the presence of MgCl<sub>2</sub> salts, primarily due to the strong local electric fields produced by the divalent Mg<sup>2+</sup> ions in the solutions.</p>","PeriodicalId":60,"journal":{"name":"The Journal of Physical Chemistry B","volume":"129 27","pages":"6954–6964"},"PeriodicalIF":2.9000,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Terahertz and Dielectric Spectroscopy of Aqueous MgCl2 Solutions: Self- and Cross-Correlation Contributions of Permanent and Induced Dipoles Using Polarizable Models\",\"authors\":\"Himanshu Kumar Vishwakarma, and , Amalendu Chandra*, \",\"doi\":\"10.1021/acs.jpcb.5c02574\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >We have investigated the terahertz (THz) and dielectric spectra of aqueous MgCl<sub>2</sub> solutions through molecular dynamics simulations using the AMOEBA polarizable force field for both water and ions. We calculated the differenceabsorption spectra for three different concentrations of MgCl<sub>2</sub> by subtracting the pure water contribution from the total absorption spectra of the solutions. The difference THz spectra of the solutions are divided into ion–ion, water–water, and ion–water components, with further resolution into self- and cross-correlations. Through these dissections, we gained insights into spectral features arising from ion–ion and ion–water correlations and also from changes in water–water correlations caused by ions. The contributions of permanent and induced dipole auto- and cross-correlations provide further insights into the nature of low-frequency vibrational modes involving cation–water and anion–water interactions. Our results reveal that the hydrogen bond stretch motion of water is suppressed by ions, whereas an additional contribution comes from the chloride ion–water hydrogen bond stretch motion. The low-frequency modes in the ion–water part are found to be mainly dominated by cation–water interactions. Furthermore, the results of the low-frequency dielectric spectra show that the relaxation of the collective dipole of water is slowed significantly in the presence of MgCl<sub>2</sub> salts, primarily due to the strong local electric fields produced by the divalent Mg<sup>2+</sup> ions in the solutions.</p>\",\"PeriodicalId\":60,\"journal\":{\"name\":\"The Journal of Physical Chemistry B\",\"volume\":\"129 27\",\"pages\":\"6954–6964\"},\"PeriodicalIF\":2.9000,\"publicationDate\":\"2025-06-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"The Journal of Physical Chemistry B\",\"FirstCategoryId\":\"1\",\"ListUrlMain\":\"https://pubs.acs.org/doi/10.1021/acs.jpcb.5c02574\",\"RegionNum\":2,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"The Journal of Physical Chemistry B","FirstCategoryId":"1","ListUrlMain":"https://pubs.acs.org/doi/10.1021/acs.jpcb.5c02574","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Terahertz and Dielectric Spectroscopy of Aqueous MgCl2 Solutions: Self- and Cross-Correlation Contributions of Permanent and Induced Dipoles Using Polarizable Models
We have investigated the terahertz (THz) and dielectric spectra of aqueous MgCl2 solutions through molecular dynamics simulations using the AMOEBA polarizable force field for both water and ions. We calculated the differenceabsorption spectra for three different concentrations of MgCl2 by subtracting the pure water contribution from the total absorption spectra of the solutions. The difference THz spectra of the solutions are divided into ion–ion, water–water, and ion–water components, with further resolution into self- and cross-correlations. Through these dissections, we gained insights into spectral features arising from ion–ion and ion–water correlations and also from changes in water–water correlations caused by ions. The contributions of permanent and induced dipole auto- and cross-correlations provide further insights into the nature of low-frequency vibrational modes involving cation–water and anion–water interactions. Our results reveal that the hydrogen bond stretch motion of water is suppressed by ions, whereas an additional contribution comes from the chloride ion–water hydrogen bond stretch motion. The low-frequency modes in the ion–water part are found to be mainly dominated by cation–water interactions. Furthermore, the results of the low-frequency dielectric spectra show that the relaxation of the collective dipole of water is slowed significantly in the presence of MgCl2 salts, primarily due to the strong local electric fields produced by the divalent Mg2+ ions in the solutions.
期刊介绍:
An essential criterion for acceptance of research articles in the journal is that they provide new physical insight. Please refer to the New Physical Insights virtual issue on what constitutes new physical insight. Manuscripts that are essentially reporting data or applications of data are, in general, not suitable for publication in JPC B.