The effects of substituent type and position on the proton transfer reaction of 3-hydroxytropolone(3-OHTRN) have been investigated theoretically by using density functional theory at the level of B3LYP/ 6-31+G** metho...The effects of substituent type and position on the proton transfer reaction of 3-hydroxytropolone(3-OHTRN) have been investigated theoretically by using density functional theory at the level of B3LYP/ 6-31+G** method. The influence of solvent on the proton transfer reactions of substituted 3-OHTRN has been examined using the self-consistent isodensity polarized continuum model(SCI-PCM) in water. As a result, while the proton transfer reaction is kinetically the easiest by substitution on position 3 of-NH2 group in the gas phase, it is kinetically the easiest by substitution on position 5 of the same group in water. In addition, these reactions are either kinetically or thermodynamically easier in the gas phase than that in water, except the reaction of structure with-NH2 group at position 6.展开更多
Real-time and on-line monitoring volatile organic compounds（VOCs） are valuable for real-time evalua- ting air quality and monitoring the key source of pollution. A self-developed proton transfer reaction-mass spectr...Real-time and on-line monitoring volatile organic compounds（VOCs） are valuable for real-time evalua- ting air quality and monitoring the key source of pollution. A self-developed proton transfer reaction-mass spectro- meter（PTR-MS） was constructed and applied to on-line monitoring trace VOCs in ambient air in Hefei, China. With the help of a self-developed catalytic converter, the background signal of the instrument was detected and the stability of the instrument was evaluated. The relative standard deviation of signal at m/z 21 was only 0.74% and the detection limit of PTR-MS was 97 part per trillion（97x 10-12, volume ratio）. As a case of the air monitoring in Hefei, the am- bient air at Dongpu reservoir spot was on-line monitored for 13 d with our self-developed PTR-MS. Meanwhile, a solid-phase micro-extraction（SPME） technique coupled to gas chromatography-mass spectrometry/mass spectrometry （GC-MS/MS） was also used for the off-line detection of the air. The results show that our self-developed PTR-MS can be used for the on-line and long-term monitoring of VOCs in air at part per trillion level, and the change trend of VOCs concentration monitored with PTR-MS was consistent with that detected with the conventional SPME-GC-MS. This self-developed PTR-MS can fully satisfy the requirements of air quality monitoring and real-time monitoring of the key pollution sources.展开更多
The theoretical uncertainties of single proton transfer cross sections of the(^(3)He,d)and(d,^(3)He)reactions,owing to the uncertainties of the entrance-and exit-channel optical model potentials,are examined with the^...The theoretical uncertainties of single proton transfer cross sections of the(^(3)He,d)and(d,^(3)He)reactions,owing to the uncertainties of the entrance-and exit-channel optical model potentials,are examined with the^(30)Si(^(3)He,d)^(31)P,^(13)B(d,^(3)He)^(12)Be,and^(34)S(^(3)He,d)^(35)Cl reactions at incident energies of 25,46,and 25 MeV,respectively,within the framework of the distorted wave Born approximation.The differential cross sections at the first peaks in the angular distributions of these reactions are found to have uncertainties of approximately 5%,owing to the uncertainties in the optical model potentials from 20,000 calculations of randomly sampled parameters.This amount of uncertainty is found to be nearly independent of the angular momentum transfer and the target masses within the studied range of incident energies.Uncertainties in the single proton spectroscopic factors obtained by matching the theoretical and experimental cross sections at different scattering angles are also discussed.展开更多
The H^++CO2 reaction at high energies is relevant in atmospheric chemistry,astrophysics,and proton cancer therapy research.Therefore,we present herein a complete investigation of H^++CO2 at ELab=30 eV with the simples...The H^++CO2 reaction at high energies is relevant in atmospheric chemistry,astrophysics,and proton cancer therapy research.Therefore,we present herein a complete investigation of H^++CO2 at ELab=30 eV with the simplest-level electron nuclear dynamics(SLEND)method.SLEND describes nuclei via classical mechanics and electrons with a singledeterminantal Thouless wavefunction.The 3402 SLEND conducted simulations from 42 independent CO2 target orientations provide a full description of all the reactive processes and their mechanisms in this system:non-charge-transfer scattering(NCTS),charge-transfer scattering(CTS),and single C=O bond dissociation;all this valuable information about reactivity is not accessible experimentally.Numerous details of the projectile scattering patterns are provided,including the appearance and coalescence of primary and secondary rainbow angles as a function of the target orientation.SLEND NCTS and CTS differential cross sections(DCSs)are evaluated in conjunction with advanced semi-classical techniques.SLEND NCTS DCS agrees well with its experimental counterpart at all the measured scattering angles,whereas SLEND CTS DCS agrees well at high scattering angles but less satisfactorily at lower ones.Remarkably,both NCTS and CTS SLEND DCSs predict the primary rainbow angle signatures in agreement with the experiment.展开更多
The spin-forbidden reaction 1HNO(1A')+OH-→3NO-(3Σ-)+H2O has been extensively explored using various CASSCF active spaces with MP2 corrections in several basis sets. Natural bond orbital (NBO) analysis, together ...The spin-forbidden reaction 1HNO(1A')+OH-→3NO-(3Σ-)+H2O has been extensively explored using various CASSCF active spaces with MP2 corrections in several basis sets. Natural bond orbital (NBO) analysis, together with the NBO energetic (deletion) analysis, indicates that the two isomers have nearly equal total energy and could compete with each other in the title reaction. More significantly, the singlet/triplet surface crossing regions have been examined and the spinorbit coupling (SOC) and energetics have been computed. The computational results indicate that the SOC is very large at the crossing point T1/S0 trans (ca.40.9 cm-1). Moreover, the T1/S0 trans has a low energy of 10.67 kcal/mol relative to that of trans-S0. Therefore, the surface crossing to the triplet state seems much more efficient at the T1/S0 trans region along the minimum energy path (MEP), However, The values of single (P1ISC) and double (P2ISC) passes estimated at T1/S0 trans show that the ISC occurs with a little probability.展开更多
利用密度泛函理论(DFT),在B3LYP/cc-pVDZ水平上,对三过氧化三丙酮(Triacetone triperoxide,TATP)及其质子化离子[TATP+H]+进行了构型优化和质子亲和势(Proton Affinity,PA)计算,研究结果表明,PA(TATP)=866.73kJ/mol大于PA(H2O)=691.0kJ/...利用密度泛函理论(DFT),在B3LYP/cc-pVDZ水平上,对三过氧化三丙酮(Triacetone triperoxide,TATP)及其质子化离子[TATP+H]+进行了构型优化和质子亲和势(Proton Affinity,PA)计算,研究结果表明,PA(TATP)=866.73kJ/mol大于PA(H2O)=691.0kJ/mol,TATP与H3O+可发生质子转移反应.在自行研制的质子转移反应质谱(Proton transfer reaction mass spectrometry,PTR-MS)装置上,研究了TATP与H3O+反应生成的特征离子.当漂移管中E/N=1.4×10-15V.cm2时,在荷质比m/z=91,75,74,59,43等处观察到了产物离子.降低E/N至0.5×10-15V.cm2后,在m/z=223处观察到了质子化产物离子([TATP+H]+),验证了计算结果;结合[TATP+H]+的构型,分析了TATP质子转移反应产物离子可能的归属及其形成过程.结合PTR-MS漂移管内E/N的改变引起m/z=223,91,43等离子的变化特征,可实现TATP的准确识别和快速定量检测,检测下限达到5.0×10-10mol/L(±50%).展开更多
采用质子传递反应-飞行时间质谱仪(Proton Transfer Reaction-Time of Flight-Mass Spectrometry,PTR-TOFMS)与气相色谱-质谱联用技术(Gas Chromatography-Mass Spectrometer,GC-MS)对不同品种武夷岩茶(水仙、肉桂)香气成分进行分析,结...采用质子传递反应-飞行时间质谱仪(Proton Transfer Reaction-Time of Flight-Mass Spectrometry,PTR-TOFMS)与气相色谱-质谱联用技术(Gas Chromatography-Mass Spectrometer,GC-MS)对不同品种武夷岩茶(水仙、肉桂)香气成分进行分析,结果表明:武夷水仙以反式橙花叔醇、(E,E)-2,4-庚二烯醛、芳樟醇及其氧化物等为主;武夷肉桂是反式橙花叔醇、α-法尼烯、苯甲醛为主,且在武夷山肉桂中存在高浓度的m/z 207、223、281、291几个未知化合物。2种分析技术所检测到的香气成分和相对含量比例差异显著,两者各有优劣,相互补充,联合分析更加完整,更有利于准确地进行香气分析,同时发现PTR-TOF-MS法更能真实地反映茶叶香气的完整信息。展开更多
文摘The effects of substituent type and position on the proton transfer reaction of 3-hydroxytropolone(3-OHTRN) have been investigated theoretically by using density functional theory at the level of B3LYP/ 6-31+G** method. The influence of solvent on the proton transfer reactions of substituted 3-OHTRN has been examined using the self-consistent isodensity polarized continuum model(SCI-PCM) in water. As a result, while the proton transfer reaction is kinetically the easiest by substitution on position 3 of-NH2 group in the gas phase, it is kinetically the easiest by substitution on position 5 of the same group in water. In addition, these reactions are either kinetically or thermodynamically easier in the gas phase than that in water, except the reaction of structure with-NH2 group at position 6.
基金Supported by the National Natural Science Foundation of China（Nos.21477132, 21577145）, the National Key Technology Research and Development Program of China（No.2015BAI01B04）, the National Key Research Program of China （No.2016YFC0200200）, the Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology of China（No.2014FXCX007） and the Functional Development Program of Instrument and Equipment in Chinese Academy of Sciences.
文摘Real-time and on-line monitoring volatile organic compounds（VOCs） are valuable for real-time evalua- ting air quality and monitoring the key source of pollution. A self-developed proton transfer reaction-mass spectro- meter（PTR-MS） was constructed and applied to on-line monitoring trace VOCs in ambient air in Hefei, China. With the help of a self-developed catalytic converter, the background signal of the instrument was detected and the stability of the instrument was evaluated. The relative standard deviation of signal at m/z 21 was only 0.74% and the detection limit of PTR-MS was 97 part per trillion（97x 10-12, volume ratio）. As a case of the air monitoring in Hefei, the am- bient air at Dongpu reservoir spot was on-line monitored for 13 d with our self-developed PTR-MS. Meanwhile, a solid-phase micro-extraction（SPME） technique coupled to gas chromatography-mass spectrometry/mass spectrometry （GC-MS/MS） was also used for the off-line detection of the air. The results show that our self-developed PTR-MS can be used for the on-line and long-term monitoring of VOCs in air at part per trillion level, and the change trend of VOCs concentration monitored with PTR-MS was consistent with that detected with the conventional SPME-GC-MS. This self-developed PTR-MS can fully satisfy the requirements of air quality monitoring and real-time monitoring of the key pollution sources.
基金supported by the National Natural Science Foundation of China(No.U2067205).
文摘The theoretical uncertainties of single proton transfer cross sections of the(^(3)He,d)and(d,^(3)He)reactions,owing to the uncertainties of the entrance-and exit-channel optical model potentials,are examined with the^(30)Si(^(3)He,d)^(31)P,^(13)B(d,^(3)He)^(12)Be,and^(34)S(^(3)He,d)^(35)Cl reactions at incident energies of 25,46,and 25 MeV,respectively,within the framework of the distorted wave Born approximation.The differential cross sections at the first peaks in the angular distributions of these reactions are found to have uncertainties of approximately 5%,owing to the uncertainties in the optical model potentials from 20,000 calculations of randomly sampled parameters.This amount of uncertainty is found to be nearly independent of the angular momentum transfer and the target masses within the studied range of incident energies.Uncertainties in the single proton spectroscopic factors obtained by matching the theoretical and experimental cross sections at different scattering angles are also discussed.
基金Present calculations were performed at the Texas Tech University High Performance Computer Center and the Texas Advanced Computing Center at the University of Texas at Austin.Prof.Morales acknowledges financial support from the Cancer Prevention and Research Institute of Texas(CPRIT)grant RP140478.Prof.Yan acknowledges the financial support from the National Natural Science Foundation of China(No.21373064)and the Program for Innovative Research Team of Guizhou Province(No.QKTD[2014]4021).
文摘The H^++CO2 reaction at high energies is relevant in atmospheric chemistry,astrophysics,and proton cancer therapy research.Therefore,we present herein a complete investigation of H^++CO2 at ELab=30 eV with the simplest-level electron nuclear dynamics(SLEND)method.SLEND describes nuclei via classical mechanics and electrons with a singledeterminantal Thouless wavefunction.The 3402 SLEND conducted simulations from 42 independent CO2 target orientations provide a full description of all the reactive processes and their mechanisms in this system:non-charge-transfer scattering(NCTS),charge-transfer scattering(CTS),and single C=O bond dissociation;all this valuable information about reactivity is not accessible experimentally.Numerous details of the projectile scattering patterns are provided,including the appearance and coalescence of primary and secondary rainbow angles as a function of the target orientation.SLEND NCTS and CTS differential cross sections(DCSs)are evaluated in conjunction with advanced semi-classical techniques.SLEND NCTS DCS agrees well with its experimental counterpart at all the measured scattering angles,whereas SLEND CTS DCS agrees well at high scattering angles but less satisfactorily at lower ones.Remarkably,both NCTS and CTS SLEND DCSs predict the primary rainbow angle signatures in agreement with the experiment.
基金the Natural Science Education Foundation of Gansu Province, China (Grant No. 021-22)
文摘The spin-forbidden reaction 1HNO(1A')+OH-→3NO-(3Σ-)+H2O has been extensively explored using various CASSCF active spaces with MP2 corrections in several basis sets. Natural bond orbital (NBO) analysis, together with the NBO energetic (deletion) analysis, indicates that the two isomers have nearly equal total energy and could compete with each other in the title reaction. More significantly, the singlet/triplet surface crossing regions have been examined and the spinorbit coupling (SOC) and energetics have been computed. The computational results indicate that the SOC is very large at the crossing point T1/S0 trans (ca.40.9 cm-1). Moreover, the T1/S0 trans has a low energy of 10.67 kcal/mol relative to that of trans-S0. Therefore, the surface crossing to the triplet state seems much more efficient at the T1/S0 trans region along the minimum energy path (MEP), However, The values of single (P1ISC) and double (P2ISC) passes estimated at T1/S0 trans show that the ISC occurs with a little probability.
文摘利用密度泛函理论(DFT),在B3LYP/cc-pVDZ水平上,对三过氧化三丙酮(Triacetone triperoxide,TATP)及其质子化离子[TATP+H]+进行了构型优化和质子亲和势(Proton Affinity,PA)计算,研究结果表明,PA(TATP)=866.73kJ/mol大于PA(H2O)=691.0kJ/mol,TATP与H3O+可发生质子转移反应.在自行研制的质子转移反应质谱(Proton transfer reaction mass spectrometry,PTR-MS)装置上,研究了TATP与H3O+反应生成的特征离子.当漂移管中E/N=1.4×10-15V.cm2时,在荷质比m/z=91,75,74,59,43等处观察到了产物离子.降低E/N至0.5×10-15V.cm2后,在m/z=223处观察到了质子化产物离子([TATP+H]+),验证了计算结果;结合[TATP+H]+的构型,分析了TATP质子转移反应产物离子可能的归属及其形成过程.结合PTR-MS漂移管内E/N的改变引起m/z=223,91,43等离子的变化特征,可实现TATP的准确识别和快速定量检测,检测下限达到5.0×10-10mol/L(±50%).
文摘采用质子传递反应-飞行时间质谱仪(Proton Transfer Reaction-Time of Flight-Mass Spectrometry,PTR-TOFMS)与气相色谱-质谱联用技术(Gas Chromatography-Mass Spectrometer,GC-MS)对不同品种武夷岩茶(水仙、肉桂)香气成分进行分析,结果表明:武夷水仙以反式橙花叔醇、(E,E)-2,4-庚二烯醛、芳樟醇及其氧化物等为主;武夷肉桂是反式橙花叔醇、α-法尼烯、苯甲醛为主,且在武夷山肉桂中存在高浓度的m/z 207、223、281、291几个未知化合物。2种分析技术所检测到的香气成分和相对含量比例差异显著,两者各有优劣,相互补充,联合分析更加完整,更有利于准确地进行香气分析,同时发现PTR-TOF-MS法更能真实地反映茶叶香气的完整信息。
