Pub Date : 2018-02-01DOI: 10.4208/JAMS.102017.121517A
Mei-Yu Zhu, Jun Song, K. Zhao
The oneand two-photon absorption, as well as the emission properties of a ratiometric zinc ion probe have been theoretically investigated employing the time-dependent density functional theory and response theory. Various coordination geometries have been considered. Special emphasis is placed on the effects of coordination mode on the optical properties. Our results demonstrate that upon combining with zinc ion, the one-photon absorption (OPA), emission and two-photon absorption (TPA) wavelengths show considerable red shift due to the enhanced internal charge transfer mechanism. Moreover, their intensities are enhanced to some extent. It is also shown that the red shifts are quite different for various coordination geometries. When the zinc ion is connected with the electron acceptor of the fluorophore, the OPA, emission and TPA wavelengths have larger red shifts induced by the lower energy gaps between the related molecular orbitals.
{"title":"Theoretical study on two-photon absorption properties of a zinc ion probe based on ICT mechanism: effects of coordination mode","authors":"Mei-Yu Zhu, Jun Song, K. Zhao","doi":"10.4208/JAMS.102017.121517A","DOIUrl":"https://doi.org/10.4208/JAMS.102017.121517A","url":null,"abstract":"The oneand two-photon absorption, as well as the emission properties of a ratiometric zinc ion probe have been theoretically investigated employing the time-dependent density functional theory and response theory. Various coordination geometries have been considered. Special emphasis is placed on the effects of coordination mode on the optical properties. Our results demonstrate that upon combining with zinc ion, the one-photon absorption (OPA), emission and two-photon absorption (TPA) wavelengths show considerable red shift due to the enhanced internal charge transfer mechanism. Moreover, their intensities are enhanced to some extent. It is also shown that the red shifts are quite different for various coordination geometries. When the zinc ion is connected with the electron acceptor of the fluorophore, the OPA, emission and TPA wavelengths have larger red shifts induced by the lower energy gaps between the related molecular orbitals.","PeriodicalId":15131,"journal":{"name":"Journal of Atomic and Molecular Sciences","volume":"9 1","pages":"152-156"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76520625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-02-01DOI: 10.4208/JAMS.101317.121217A
X. Zhuang, Ju‐Beom Song, Luyan Sun, Tiantian Wang, Xinguo Liu
Stereodynamics for Li+DF/TF→LiF+D/T reactions are studied using the quasi-classical trajectory method based on a new potential energy surface constructed by Aguado and Paniaga [J. Chem. Phys. 119 (2003) 10088]. The product angular distributions of and , which reflect the vector correlation, are calculated and discussed. The average rotational alignment factor 〈 〉 as function of the collision energy is also presented. Furthermore, four polarization-dependent differential cross sections (PDDCSs), namely, PDDCS00, PDDCS20, PDDCS21and PDDCS22+ are calculated as well. By comparing the stereodynamics results of the title reactions, we find that the isotopic effects are relatively obvious.
{"title":"Influences of the low collision energies and isotopic variants on the stereodynamics for reactions Li+DF/TF→LiF+D/T","authors":"X. Zhuang, Ju‐Beom Song, Luyan Sun, Tiantian Wang, Xinguo Liu","doi":"10.4208/JAMS.101317.121217A","DOIUrl":"https://doi.org/10.4208/JAMS.101317.121217A","url":null,"abstract":"Stereodynamics for Li+DF/TF→LiF+D/T reactions are studied using the quasi-classical trajectory method based on a new potential energy surface constructed by Aguado and Paniaga [J. Chem. Phys. 119 (2003) 10088]. The product angular distributions of and , which reflect the vector correlation, are calculated and discussed. The average rotational alignment factor 〈 〉 as function of the collision energy is also presented. Furthermore, four polarization-dependent differential cross sections (PDDCSs), namely, PDDCS00, PDDCS20, PDDCS21and PDDCS22+ are calculated as well. By comparing the stereodynamics results of the title reactions, we find that the isotopic effects are relatively obvious.","PeriodicalId":15131,"journal":{"name":"Journal of Atomic and Molecular Sciences","volume":"32 1","pages":"117-121"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78537132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-02-01DOI: 10.4208/JAMS.110117.121717A
Jiancai Leng, Jie Sun, Yu-jin Zhang
Abstract. The nonlinear optical properties of porphyrins (Cu porphyrin, Zn porphyrin and H2MHTP) and their covalently linked composites with graphene oxide (GO) have been studied by numerically solving the rate equations and field intensity equation with an iterative predictor-corrector finite-difference time-domain technique. The three-level scheme is introduced to illustrate the interaction between the molecules and laser in picosecond time domain. The optical limiting and dynamical two-photon absorption are investigated. Our numerical results show that GO-porphyrin composites show enhanced nonlinear absorption properties compared with individual porphyrin molecules due to the strong electron acceptor capability of the GO moeity, which agrees with the experimental measurements. Moreover, the dependence of the thickness of the absorber and the pulse duration on the two-photon absorption cross sections of the medium are discussed, indicating that one can modulate the dynamical two-photon absorption process by regulating the paremeters of the medium and the laser.
{"title":"Nonlinear optical properties of metal/metal free porphyrins and their graphene oxide composites in picosecond regime","authors":"Jiancai Leng, Jie Sun, Yu-jin Zhang","doi":"10.4208/JAMS.110117.121717A","DOIUrl":"https://doi.org/10.4208/JAMS.110117.121717A","url":null,"abstract":"Abstract. The nonlinear optical properties of porphyrins (Cu porphyrin, Zn porphyrin and H2MHTP) and their covalently linked composites with graphene oxide (GO) have been studied by numerically solving the rate equations and field intensity equation with an iterative predictor-corrector finite-difference time-domain technique. The three-level scheme is introduced to illustrate the interaction between the molecules and laser in picosecond time domain. The optical limiting and dynamical two-photon absorption are investigated. Our numerical results show that GO-porphyrin composites show enhanced nonlinear absorption properties compared with individual porphyrin molecules due to the strong electron acceptor capability of the GO moeity, which agrees with the experimental measurements. Moreover, the dependence of the thickness of the absorber and the pulse duration on the two-photon absorption cross sections of the medium are discussed, indicating that one can modulate the dynamical two-photon absorption process by regulating the paremeters of the medium and the laser.","PeriodicalId":15131,"journal":{"name":"Journal of Atomic and Molecular Sciences","volume":"73 1","pages":"105-109"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80449919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. To investigate the orientations of CO molecule driven by both Gaussian and square laser pulses, we give the theoretical analysis using the density matrix method and rigid rotor approximation. The results show that both pulses with a short duration can induce the in-pulse and post-pulse orientations easily, and that the field-free molecular orientation in both non-adiabatic and adiabatic regimes can be obtained by square laser pulse. In addition, the discussion of the temperature effect for field-free orientation shows that the square laser pulse is more feasible in an ensemble of higher temperature.
{"title":"Comparison of Gaussian and square laser pulses on molecular orientation","authors":"Jingsong Liu, Qiyuan Cheng, Daguang Yue, Xu-Cong Zhou, Q. Meng","doi":"10.4208/JAMS.110917.122917A","DOIUrl":"https://doi.org/10.4208/JAMS.110917.122917A","url":null,"abstract":"Abstract. To investigate the orientations of CO molecule driven by both Gaussian and square laser pulses, we give the theoretical analysis using the density matrix method and rigid rotor approximation. The results show that both pulses with a short duration can induce the in-pulse and post-pulse orientations easily, and that the field-free molecular orientation in both non-adiabatic and adiabatic regimes can be obtained by square laser pulse. In addition, the discussion of the temperature effect for field-free orientation shows that the square laser pulse is more feasible in an ensemble of higher temperature.","PeriodicalId":15131,"journal":{"name":"Journal of Atomic and Molecular Sciences","volume":"19 1","pages":"113-116"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79213577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-02-01DOI: 10.4208/jams.101317.121817a
Jian Li, Y. Huo, Fengcai Ma
Abstact. We report a theoretical study of low-energy structures (LES) in the process of the strong-field ionization in the velocity gauge when considering non-dipole approximation and Coulomb corrections respectively. Comparisons have been made between considering non-dipole approximation and Coulomb corrections. A derivation of the photoelectron energy spectra for a hydrogen atom in a strong linearly polarized laser field is presented, which is considering non-dipole approximation and Coulomb corrections in the ground state. Based on the quantum and semiclassical analysis, we calculate ionization rates changed with the energy and variable regular changed with the wavelength and intensity have been also discussed.
{"title":"The study on ionization of hydrogen atoms in a laser field considering non-dipole approximation and Coulomb corrections","authors":"Jian Li, Y. Huo, Fengcai Ma","doi":"10.4208/jams.101317.121817a","DOIUrl":"https://doi.org/10.4208/jams.101317.121817a","url":null,"abstract":"Abstact. We report a theoretical study of low-energy structures (LES) in the process of the strong-field ionization in the velocity gauge when considering non-dipole approximation and Coulomb corrections respectively. Comparisons have been made between considering non-dipole approximation and Coulomb corrections. A derivation of the photoelectron energy spectra for a hydrogen atom in a strong linearly polarized laser field is presented, which is considering non-dipole approximation and Coulomb corrections in the ground state. Based on the quantum and semiclassical analysis, we calculate ionization rates changed with the energy and variable regular changed with the wavelength and intensity have been also discussed.","PeriodicalId":15131,"journal":{"name":"Journal of Atomic and Molecular Sciences","volume":"15 3 1","pages":"110-112"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82582284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-02-01DOI: 10.4208/JAMS.102217.121217A
Li Guo, Yulong Xu
DFT and ab initio methods are used to investigate why the reaction, C(1)F3S(2)O2O(3)C(4)F2C(5)F3 + F − , results in the S-O cleavage chemospecifically. Three SN2 channels, i.e. S-O cleavage and backand frontside of C-O scission are predicted to occur. The F(11)and F(12) atoms of the C(4)F2 group play the multiple roles in three paths. Multi-membered rings are formed in C-O rupture mechanisms due to the neighboring effect. The rate of S-O scission reaction is 10 31 time as large as the rates of C-O rupture reactions. It is the combination of the irreversibility and the huge rate ratios to determine that S-O cleavage is chemospecific. This conclusion agrees well with the experimental results.
{"title":"Theoretical study on chemospecificity of CF_3SO_3CF_2CF_3 + F^{−} reactions","authors":"Li Guo, Yulong Xu","doi":"10.4208/JAMS.102217.121217A","DOIUrl":"https://doi.org/10.4208/JAMS.102217.121217A","url":null,"abstract":"DFT and ab initio methods are used to investigate why the reaction, C(1)F3S(2)O2O(3)C(4)F2C(5)F3 + F − , results in the S-O cleavage chemospecifically. Three SN2 channels, i.e. S-O cleavage and backand frontside of C-O scission are predicted to occur. The F(11)and F(12) atoms of the C(4)F2 group play the multiple roles in three paths. Multi-membered rings are formed in C-O rupture mechanisms due to the neighboring effect. The rate of S-O scission reaction is 10 31 time as large as the rates of C-O rupture reactions. It is the combination of the irreversibility and the huge rate ratios to determine that S-O cleavage is chemospecific. This conclusion agrees well with the experimental results.","PeriodicalId":15131,"journal":{"name":"Journal of Atomic and Molecular Sciences","volume":"71 1","pages":"146-151"},"PeriodicalIF":0.0,"publicationDate":"2018-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83891946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-10-01DOI: 10.4208/JAMS.080117.091717A
H. Ma, L. Guo, Q. Guo, Y. Li
{"title":"Accurate ab initio-based potential energy curve and spectroscopic properties of NO(X²Π) via extrapolation to the complete basis set limit","authors":"H. Ma, L. Guo, Q. Guo, Y. Li","doi":"10.4208/JAMS.080117.091717A","DOIUrl":"https://doi.org/10.4208/JAMS.080117.091717A","url":null,"abstract":"","PeriodicalId":15131,"journal":{"name":"Journal of Atomic and Molecular Sciences","volume":"21 1","pages":"75-83"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74445790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-10-01DOI: 10.4208/jams.052817.081017a
L. Guo, H. Ma, W. Shi, L. L. Zhang, Y. Z. Song, Q. Guo, Y. Li
. Potential energy curves (PECs) for the ground electronic state of NS are acquired by means of fitting the ab initio energies computed at the multi-reference configuration interaction method with the Davidson correction in combination with a series of correlation-consistent basis sets from Dunning: aug-cc-pVXZ (X = T, Q, 5 and 6). In order to obtain PECs with high accuracy, the PECs computed with aug-cc-pV(Q,5)Z basis sets are extrapolated to the complete basis set limit. Such PECs are then used to fit the analytical potential energy functions (APEFs) with the extended Hartree–Fock approximate correlation energy method. Based on the APEFs of NS(X 2 Π), reliable and accurate spectroscopic parameters are obtained. By solving the radial Schrödinger equation numerically, we can acquire the complete set of vibrational levels, inertial rotation constant, centrifugal distortion constants and classical turning points when J = 0. As a whole, our research data can be regarded as a reference for prospective research on the NS molecule.
{"title":"Accurate potential energy function and spectroscopic properties of NS (X²Π) via extrapolation to the complete basis set limit","authors":"L. Guo, H. Ma, W. Shi, L. L. Zhang, Y. Z. Song, Q. Guo, Y. Li","doi":"10.4208/jams.052817.081017a","DOIUrl":"https://doi.org/10.4208/jams.052817.081017a","url":null,"abstract":". Potential energy curves (PECs) for the ground electronic state of NS are acquired by means of fitting the ab initio energies computed at the multi-reference configuration interaction method with the Davidson correction in combination with a series of correlation-consistent basis sets from Dunning: aug-cc-pVXZ (X = T, Q, 5 and 6). In order to obtain PECs with high accuracy, the PECs computed with aug-cc-pV(Q,5)Z basis sets are extrapolated to the complete basis set limit. Such PECs are then used to fit the analytical potential energy functions (APEFs) with the extended Hartree–Fock approximate correlation energy method. Based on the APEFs of NS(X 2 Π), reliable and accurate spectroscopic parameters are obtained. By solving the radial Schrödinger equation numerically, we can acquire the complete set of vibrational levels, inertial rotation constant, centrifugal distortion constants and classical turning points when J = 0. As a whole, our research data can be regarded as a reference for prospective research on the NS molecule.","PeriodicalId":15131,"journal":{"name":"Journal of Atomic and Molecular Sciences","volume":"44 1","pages":"88-96"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73547622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Diphenyl disulfide (DPDS) finds a wide range of applications in organic synthesis, polymer manufacture, and other fields. The structure of the DPDS molecule makes it amenable to monitor by Raman spectroscopy. Studying the fate of DPDS in the course of chemical reactions is of great significance for delineating mechanisms. In this work, the normal Raman and surface-enhanced Raman spectroscopy (SERS) signals of DPDS in ethanol solution have been characterized. In ethanol solution, the Raman signals of DPDS are completely obscured by the solvent signal. However, after irradiation for more than 10 s, a characteristic peak of DPDS appears at =2544 cm −1 (in both normal Raman and SERS), and a further peak at =1582 cm −1 appears in the SERS spectrum. Hence, in situ measurement and monitoring of DPDS in ethanol solution by SERS is feasible. It would allow us to reveal the micro mechanisms of chemical reactions, determine kinetic characteristics, estimate reasonable reaction end points, improve reaction selectivity, assess the quality and yield of the product, and so on.
{"title":"In Situ Measurement and Monitoring of Diphenyl Disulfide in Ethanol Solution by SERS","authors":"Shiwei Wu, Yu Liu, Jing Wang, Caiqing Ma, Yao Zhang, Lixin Xia","doi":"10.4208/jams.060417.090517a","DOIUrl":"https://doi.org/10.4208/jams.060417.090517a","url":null,"abstract":"Diphenyl disulfide (DPDS) finds a wide range of applications in organic synthesis, polymer manufacture, and other fields. The structure of the DPDS molecule makes it amenable to monitor by Raman spectroscopy. Studying the fate of DPDS in the course of chemical reactions is of great significance for delineating mechanisms. In this work, the normal Raman and surface-enhanced Raman spectroscopy (SERS) signals of DPDS in ethanol solution have been characterized. In ethanol solution, the Raman signals of DPDS are completely obscured by the solvent signal. However, after irradiation for more than 10 s, a characteristic peak of DPDS appears at =2544 cm −1 (in both normal Raman and SERS), and a further peak at =1582 cm −1 appears in the SERS spectrum. Hence, in situ measurement and monitoring of DPDS in ethanol solution by SERS is feasible. It would allow us to reveal the micro mechanisms of chemical reactions, determine kinetic characteristics, estimate reasonable reaction end points, improve reaction selectivity, assess the quality and yield of the product, and so on.","PeriodicalId":15131,"journal":{"name":"Journal of Atomic and Molecular Sciences","volume":"143 2","pages":"84-87"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72468339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-10-01DOI: 10.4208/jams.071617.090517a
Jiyu Wang, Jing Wang, Caiqing Ma, Meixia Zhang, Yong Ding, P. Song, Fengcai Ma
. In this study, we experimentally investigated the substituent effect on benzoic acid where the mercapto group was located in different positions, namely as 2-mercaptobenzoic acid (2-MBA), 3-mercaptobenzoic acid (3-MBA) and 4-mercaptobenzoic acid (4-MBA). The substituent effect was found to have an influence on the surface plasmon-catalysed reaction on the surface of the Ag4 atoms in the reaction of MBA with silver sol. In addition to the direct evidence from the surface-enhanced Raman scattering (SERS), the chemical enhancement mechanism for the generation of the MBA–Ag complex is presented. In contrast with the normal Raman scattering (NRS) spectra, new signals appeared in the SERS spectra of 2-MBA, 3-MBA and 4-MBA under the theoretical and experimental conditions. On investigation of the SERS spectra, the characteristic peaks of the C≡C bond have been demonstrated. The structural, atomic and chemical bond properties of the three types of MBAs indicate that the S atom of the mercapto group in the MBA molecules is the position site that attaches to the silver substrate through the bond of S∙∙∙Ag, and under laser irradiation, “hot electrons” are generated between the surface of MBA and Ag4 atoms. With the effect of “hot electrons”, the –COOH bond of the MBA molecules is broken, and then the two single carboxylate MBA molecules become dimerized thiophenol acetylene (TPA). To briefly consider the substituent effect, the SERS spectra of these three types of MBAs were specifically studied for the enhancement of the Raman signal intensity with a variational tendency evident. Therefore, the conclusion was reached that the substituent effect plays a vital role in the surface plasmon-catalysed reaction, where the changing of the surface-enhanced Raman intensity was demonstrated.
{"title":"The mechanism research for the surface plasmon-catalysed reaction of the mercapto group substituted benzoic acid","authors":"Jiyu Wang, Jing Wang, Caiqing Ma, Meixia Zhang, Yong Ding, P. Song, Fengcai Ma","doi":"10.4208/jams.071617.090517a","DOIUrl":"https://doi.org/10.4208/jams.071617.090517a","url":null,"abstract":". In this study, we experimentally investigated the substituent effect on benzoic acid where the mercapto group was located in different positions, namely as 2-mercaptobenzoic acid (2-MBA), 3-mercaptobenzoic acid (3-MBA) and 4-mercaptobenzoic acid (4-MBA). The substituent effect was found to have an influence on the surface plasmon-catalysed reaction on the surface of the Ag4 atoms in the reaction of MBA with silver sol. In addition to the direct evidence from the surface-enhanced Raman scattering (SERS), the chemical enhancement mechanism for the generation of the MBA–Ag complex is presented. In contrast with the normal Raman scattering (NRS) spectra, new signals appeared in the SERS spectra of 2-MBA, 3-MBA and 4-MBA under the theoretical and experimental conditions. On investigation of the SERS spectra, the characteristic peaks of the C≡C bond have been demonstrated. The structural, atomic and chemical bond properties of the three types of MBAs indicate that the S atom of the mercapto group in the MBA molecules is the position site that attaches to the silver substrate through the bond of S∙∙∙Ag, and under laser irradiation, “hot electrons” are generated between the surface of MBA and Ag4 atoms. With the effect of “hot electrons”, the –COOH bond of the MBA molecules is broken, and then the two single carboxylate MBA molecules become dimerized thiophenol acetylene (TPA). To briefly consider the substituent effect, the SERS spectra of these three types of MBAs were specifically studied for the enhancement of the Raman signal intensity with a variational tendency evident. Therefore, the conclusion was reached that the substituent effect plays a vital role in the surface plasmon-catalysed reaction, where the changing of the surface-enhanced Raman intensity was demonstrated.","PeriodicalId":15131,"journal":{"name":"Journal of Atomic and Molecular Sciences","volume":"87 1","pages":"70-74"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85936884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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