Photodissociation dynamics of dichlorodifluoromethane (CF2Cl2) around 235 nm has been studied using the time-sliced velocity map imaging technology in combination with the resonance enhanced multi-photon ionization te...Photodissociation dynamics of dichlorodifluoromethane (CF2Cl2) around 235 nm has been studied using the time-sliced velocity map imaging technology in combination with the resonance enhanced multi-photon ionization technology. By measuring the raw images of chlorine atoms which are formed via one-photon dissociation of CF2Cl2, the speed and angular distributions can be directly obtained. The speed distribution of excited-state chlorine atoms consists of high translation energy (ET) and low ET components, which are related to direct dissociation on 3Q0 state and predissociation on the ground state induced by internal conversion, respectively. The speed distribution of ground-state chlorine atoms also consists of high ET and low ET components which are related to predissociation between 3Q0 and 1Q1 states and predissociation on the ground state induced by internal conversion, respectively. Radical dissociation channel is confirmed, nevertheless, secondary dissociation and three-body dissociation channels are excluded.展开更多
In this work,we used time-sliced ion velocity imaging to study the photodissociation dynamics of Mg O at 193 nm.Three dissociation pathways are found through the speed and angular distributions of magnesium.One pathwa...In this work,we used time-sliced ion velocity imaging to study the photodissociation dynamics of Mg O at 193 nm.Three dissociation pathways are found through the speed and angular distributions of magnesium.One pathway is the one-photon excitation of Mg O(X^(1)∑^(+))to Mg O(G^(1)Π)followed by spin-orbit coupling between the G^(1)Π,3^(3)Πand ^(1^(5))Πstates,and finally dissociated to the Mg(^(3)Pu)+O(^(3)Pg)along the 1^(5)Πsurface.The other two pathways are one-photon absorption of Mg O(A^(1)Π)state to Mg O(G^(1)Π)and Mg O(4^(1)Π)state to dissociate into Mg(^(3)P_(u))+O(^(3)P_(g))and Mg(^(1)S_(g))+O(^(1)S_(g)),respectively.The anisotropy parameters of the dissociation pathways are related to the lifetime of the vibrational energy levels and the coupling of rotational and vibronic spin-orbit states.The total kinetic energy analysis gives D0(Mg-O)=21645±50 cm^(-1).展开更多
The photodissociation dynamics of Al O at 193 nm is studied using time-sliced ion velocity mapping.Two dissociation channels are found through the speed and angular distributions of aluminum ions:one is one-photon dis...The photodissociation dynamics of Al O at 193 nm is studied using time-sliced ion velocity mapping.Two dissociation channels are found through the speed and angular distributions of aluminum ions:one is one-photon dissociation of the neutral AlO to generate Al(2 Pu)+O(3 Pg),and the other is two-photon ionization and then dissociation of AlO^+to generate Al^+(1 Sg)+O(3 Pg).Each dissociation channel includes the contribution of AlO in the vibrational states v=0-2.The anisotropy parameter of the neutral dissociation channel is more dependent on the vibration state of AlO than the ion dissociation channel.展开更多
The H+H2 reaction is the simplest chemical reaction system and has long been the prototype model in the study of reaction dynamics. Here we report a high resolution experimental investigation of the state-to-state rea...The H+H2 reaction is the simplest chemical reaction system and has long been the prototype model in the study of reaction dynamics. Here we report a high resolution experimental investigation of the state-to-state reaction dynamics in the H+HD→H2+D reaction by using the crossed molecular beams method and velocity map ion imaging technique at the collision energy of 1.17 eV. D atom products in this reaction were probed by the near threshold 1+1'(vacuum ultraviolet+ultraviolet) laser ionization scheme. The ion image with both high angular and energy resolution were acquired. State-to-state differential cross sections was accurately derived. Fast forward scattering oscillations, relating with interference effects in the scattering process, were clearly observed for H2 products at H2(v'=0,j'=1) and H2(v'=0,j'=3) rovibrational levels. This study further demonstrates the importance of measuring high-resolution differential cross sections in the study of state-to-state reaction dynamics in the gas phase.展开更多
One of the themes of modern molecular reac tion dynamics is to charac terize elementary chemical reactions from“quan tum state to quan tum stat e”,and the study of molecular reaction dynamics in excited states can h...One of the themes of modern molecular reac tion dynamics is to charac terize elementary chemical reactions from“quan tum state to quan tum stat e”,and the study of molecular reaction dynamics in excited states can help test the validi ty of modern chemical t heories and provide met hods to cont rol chemical reactions.The subject of this review is to describe the recent experimental techniques used to study the reaction dynamics of metal atoms in the gas phase.Through these techniques,information such as the internal energy distribution and angular distribution of the nascent products or the three-dimensional stereodynamic reactivity can be obtained.In addition,by preparing metal at oms wi th specific exci ted elec tronic states or orbi tal arrangemen ts,information about the reactivity of the electronic states enriches the relevant understanding of the electron transfer mechanism in metal reaction dynamics.展开更多
The reaction dynamics of yttrium atoms with sulfur dioxide molecules at a high collision energy of 36 kcal/mol was studied using time-sliced velocity map ion imaging,crossed molecular beam and laser-ablation method.Th...The reaction dynamics of yttrium atoms with sulfur dioxide molecules at a high collision energy of 36 kcal/mol was studied using time-sliced velocity map ion imaging,crossed molecular beam and laser-ablation method.The product YO was detected via multiphoton ionization at various wavelengths in the region of 482-615 nm.The slice images of YO show a broad velocity distribution and forward-backward peaking angular distribution.The forward scattering signal is stronger than its backward distribution.This indicates that the reaction proceeds via an intermediate complex and the lifetime of the intermediate state is less than one rotational period.The formation of complex suggests that electron transfer occurs in the oxidation reaction.展开更多
SiO is a wide-spread molecule found in interstellar space.Previous research has primarily focused on its spectroscopy,while its photodissociation dynamics is elusive to study due to high dissociation energy.Using time...SiO is a wide-spread molecule found in interstellar space.Previous research has primarily focused on its spectroscopy,while its photodissociation dynamics is elusive to study due to high dissociation energy.Using time-sliced ion velocity imaging technique,we observed the Si(^(3)P)+O(^(3)P)photodissociation process resulting from the excitation of highly vibrationally excited SiO(X^(1)Σ^(+),υ=13-18)molecules to the SiO(A^(1)Π,E^(1)Σ^(+))states at 193 nm.The vibrationally excited SiO molecules were generated via laser ablation of silicon rod with the collision of the oxygen molecular beam acting as carrier gas and reaction gas.The bond dissociation energy D_(e)(Si-O)is determined to be 67253±110 cm^(-1)(8.34±0.01 eV)based on the kinetic energy distribution spectrum.The SiO photodissociation study has deepened our understanding of the mechanisms of silicon chemistry for silica-rich rocky meteors as they burn in the Earth's atmosphere,and the dissociation of SiO from ablation of meteoroids following ultraviolet photon absorption.展开更多
基金supported by the National Natural Science Foundation of China(21073187,21273212,21173205)National Key Basic Research Program of China(973)(2010CB923302)+1 种基金100 Talents Program of Chinese Academy of SciencesKnowledge Innovation Program of Chinese Academy of Sciences,and USTC-NSRL Joint Funds,China(KY2340000021)~~
基金supported by the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No.17KJB150005 and No.17KJD510001)the Natural Science Foundation of Changzhou Institute of Technology (No.YN1507 and No.YN1611)+1 种基金Undergraduate Training Program for Innovation of Changzhou Institute of Technology (No.2017276Y)the National Natural Science Foundation of China (No.21273212)
文摘Photodissociation dynamics of dichlorodifluoromethane (CF2Cl2) around 235 nm has been studied using the time-sliced velocity map imaging technology in combination with the resonance enhanced multi-photon ionization technology. By measuring the raw images of chlorine atoms which are formed via one-photon dissociation of CF2Cl2, the speed and angular distributions can be directly obtained. The speed distribution of excited-state chlorine atoms consists of high translation energy (ET) and low ET components, which are related to direct dissociation on 3Q0 state and predissociation on the ground state induced by internal conversion, respectively. The speed distribution of ground-state chlorine atoms also consists of high ET and low ET components which are related to predissociation between 3Q0 and 1Q1 states and predissociation on the ground state induced by internal conversion, respectively. Radical dissociation channel is confirmed, nevertheless, secondary dissociation and three-body dissociation channels are excluded.
基金supported by the National Natural Science Foundation of China(No.22073019 and No.21673047)the Shanghai Key Laboratory Foundation of Molecular Catalysis and Innovative Materialsthe Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning。
文摘In this work,we used time-sliced ion velocity imaging to study the photodissociation dynamics of Mg O at 193 nm.Three dissociation pathways are found through the speed and angular distributions of magnesium.One pathway is the one-photon excitation of Mg O(X^(1)∑^(+))to Mg O(G^(1)Π)followed by spin-orbit coupling between the G^(1)Π,3^(3)Πand ^(1^(5))Πstates,and finally dissociated to the Mg(^(3)Pu)+O(^(3)Pg)along the 1^(5)Πsurface.The other two pathways are one-photon absorption of Mg O(A^(1)Π)state to Mg O(G^(1)Π)and Mg O(4^(1)Π)state to dissociate into Mg(^(3)P_(u))+O(^(3)P_(g))and Mg(^(1)S_(g))+O(^(1)S_(g)),respectively.The anisotropy parameters of the dissociation pathways are related to the lifetime of the vibrational energy levels and the coupling of rotational and vibronic spin-orbit states.The total kinetic energy analysis gives D0(Mg-O)=21645±50 cm^(-1).
基金supported by the National Natural Science Foundation of China(No.21673047,No.21327901,No.21573047)the Shanghai Key Laboratory Foundation of Molecular Catalysis and Innovative Materialsthe Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning。
文摘The photodissociation dynamics of Al O at 193 nm is studied using time-sliced ion velocity mapping.Two dissociation channels are found through the speed and angular distributions of aluminum ions:one is one-photon dissociation of the neutral AlO to generate Al(2 Pu)+O(3 Pg),and the other is two-photon ionization and then dissociation of AlO^+to generate Al^+(1 Sg)+O(3 Pg).Each dissociation channel includes the contribution of AlO in the vibrational states v=0-2.The anisotropy parameter of the neutral dissociation channel is more dependent on the vibration state of AlO than the ion dissociation channel.
基金supported by the National Key R&D Program of China (No.2016YFF0200500)the National Natural Science Foundation of China (No.21473173, No.21590802, No.21403207, No.21503206)the Strategic Priority Research Program of Chinese Academy of Sciences (No.XDB17000000)
文摘The H+H2 reaction is the simplest chemical reaction system and has long been the prototype model in the study of reaction dynamics. Here we report a high resolution experimental investigation of the state-to-state reaction dynamics in the H+HD→H2+D reaction by using the crossed molecular beams method and velocity map ion imaging technique at the collision energy of 1.17 eV. D atom products in this reaction were probed by the near threshold 1+1'(vacuum ultraviolet+ultraviolet) laser ionization scheme. The ion image with both high angular and energy resolution were acquired. State-to-state differential cross sections was accurately derived. Fast forward scattering oscillations, relating with interference effects in the scattering process, were clearly observed for H2 products at H2(v'=0,j'=1) and H2(v'=0,j'=3) rovibrational levels. This study further demonstrates the importance of measuring high-resolution differential cross sections in the study of state-to-state reaction dynamics in the gas phase.
基金The work was supported by the National Natural Science Foundation of China(No.21673047 and No.22073019)the Shanghai Key Laboratory Foundation of Molecular Catalysis and Innovative Materialsthe Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.
文摘One of the themes of modern molecular reac tion dynamics is to charac terize elementary chemical reactions from“quan tum state to quan tum stat e”,and the study of molecular reaction dynamics in excited states can help test the validi ty of modern chemical t heories and provide met hods to cont rol chemical reactions.The subject of this review is to describe the recent experimental techniques used to study the reaction dynamics of metal atoms in the gas phase.Through these techniques,information such as the internal energy distribution and angular distribution of the nascent products or the three-dimensional stereodynamic reactivity can be obtained.In addition,by preparing metal at oms wi th specific exci ted elec tronic states or orbi tal arrangemen ts,information about the reactivity of the electronic states enriches the relevant understanding of the electron transfer mechanism in metal reaction dynamics.
基金supported by the National Natural Science Foundation of China (No.21673047,No.21327901and No.21573047)the Shanghai Key Laboratory Foundation of Molecular Catalysis and Innovative Materialsthe Program for Professor of Special Appointment(Eastern Scholar) at Shanghai Institutions of Higher Learning.
文摘The reaction dynamics of yttrium atoms with sulfur dioxide molecules at a high collision energy of 36 kcal/mol was studied using time-sliced velocity map ion imaging,crossed molecular beam and laser-ablation method.The product YO was detected via multiphoton ionization at various wavelengths in the region of 482-615 nm.The slice images of YO show a broad velocity distribution and forward-backward peaking angular distribution.The forward scattering signal is stronger than its backward distribution.This indicates that the reaction proceeds via an intermediate complex and the lifetime of the intermediate state is less than one rotational period.The formation of complex suggests that electron transfer occurs in the oxidation reaction.
基金supported by the National Natural Science Foundation of China(No.22073019 and No.21327901)the Shanghai Key Laboratory Foundation of Molecular Catalysis and Innovative Materials,and the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.
文摘SiO is a wide-spread molecule found in interstellar space.Previous research has primarily focused on its spectroscopy,while its photodissociation dynamics is elusive to study due to high dissociation energy.Using time-sliced ion velocity imaging technique,we observed the Si(^(3)P)+O(^(3)P)photodissociation process resulting from the excitation of highly vibrationally excited SiO(X^(1)Σ^(+),υ=13-18)molecules to the SiO(A^(1)Π,E^(1)Σ^(+))states at 193 nm.The vibrationally excited SiO molecules were generated via laser ablation of silicon rod with the collision of the oxygen molecular beam acting as carrier gas and reaction gas.The bond dissociation energy D_(e)(Si-O)is determined to be 67253±110 cm^(-1)(8.34±0.01 eV)based on the kinetic energy distribution spectrum.The SiO photodissociation study has deepened our understanding of the mechanisms of silicon chemistry for silica-rich rocky meteors as they burn in the Earth's atmosphere,and the dissociation of SiO from ablation of meteoroids following ultraviolet photon absorption.
