Understanding the low-temperature chemistry of ammonia(NH3)and its interaction with hydrocarbon chemistry is a significant challenge in the kinetics of ammonia blended fuel combustion,especially with the growing in...Understanding the low-temperature chemistry of ammonia(NH3)and its interaction with hydrocarbon chemistry is a significant challenge in the kinetics of ammonia blended fuel combustion,especially with the growing interest in novel combustion concepts and the increasing use of NH3 as an energy carrier.Carbon-nitrogen(C—N)interactions play an important role in the combustion characteristic of NH3 blends with hydrocarbon fuels.In this work,the kinetics of two possible C—N interaction reactions,H-atom abstractions from NH3 and aminoxyl radical(CH3O2)by methylperoxy radical(CH3O2),is investigated.These reaction pathways show some sensitiv--ity to the low-temperature ignition of NH3/CH4.However,they have not been considered in any combustion kinetic models so far.Due to the intrinsic multi-reference nature of their transition states,the energy barriers for the two reactions are determined using the CASPT2/aug-cc-pVTZ method with the active space of(7e,7o),and CASPT2/cc-pVDZ method with the active space of(14e,12o),respectively,based on the optimized geometries and rovibrational properties obtained at M06-2X/6-311++G(d,p)level of theory.The rate constants for the two reactions in the temperature range 298.15—2000 K are calculated by using transition state theory.By incorporating these two reaction pathways with our calculated rate constants into a NH3/CH4 kinetic model,the predicted lowtemperature ignition delay times(IDT)of NH3/CH4 mixtures become noticeably shorter.展开更多
The electromagnetic shift of energy levels of H-atom electrons is determined by calculating an electron coupling to the Gibbons-Hawking ectromagnetic field thermal bath. Energy shift of electrons in H-atom is determin...The electromagnetic shift of energy levels of H-atom electrons is determined by calculating an electron coupling to the Gibbons-Hawking ectromagnetic field thermal bath. Energy shift of electrons in H-atom is determined in the framework of non-relativistic quantum mechanics.展开更多
Based on recent advances in attosecond strong-field spectroscopy and the current feasibility for trapping individual groundstate H-atoms from a neon-gas matrix, an experiment to probe the groundstate motion of the ele...Based on recent advances in attosecond strong-field spectroscopy and the current feasibility for trapping individual groundstate H-atoms from a neon-gas matrix, an experiment to probe the groundstate motion of the electron in the H-atom is proposed here.展开更多
近年来,直接光激发芳酮介导的氢原子转移反应在有机合成领域受到一定关注。芳酮可在光激发后通过氢原子转移(Hydrogen Atom Transfer,HAT)过程活化底物中的C(sp3)-H键,生成相应的自由基中间体。将该类催化剂与电化学手段相结合,构建...近年来,直接光激发芳酮介导的氢原子转移反应在有机合成领域受到一定关注。芳酮可在光激发后通过氢原子转移(Hydrogen Atom Transfer,HAT)过程活化底物中的C(sp3)-H键,生成相应的自由基中间体。将该类催化剂与电化学手段相结合,构建电光催化体系,可在无外加氧化剂和金属试剂的温和条件下实现多种惰性化学键的转化。综述了该领域的研究进展,重点介绍了利用芳酮的双重催化功能实现的几类反应,包括杂芳烃的C(sp2)-H烷基化、酰基化、硅基化环化及硼化反应。这些研究通过从甲酰胺、醛、有机硅烷及硼烷络合物等前体中直接生成酰基、磷酰基、硅基及硼基自由基,为含氮杂环及羰基化合物的高效合成提供了多样化选择的途径。展开更多
摘要Understanding the low-temperature chemistry of ammonia(NH3)and its interaction with hydrocarbon chemistry is a significant challenge in the kinetics of ammonia blended fuel combustion,especially with the growing interest in novel combustion concepts and the increasing use of NH3 as an energy carrier.Carbon-nitrogen(C—N)interactions play an important role in the combustion characteristic of NH3 blends with hydrocarbon fuels.In this work,the kinetics of two possible C—N interaction reactions,H-atom abstractions from NH3 and aminoxyl radical(CH3O2)by methylperoxy radical(CH3O2),is investigated.These reaction pathways show some sensitiv--ity to the low-temperature ignition of NH3/CH4.However,they have not been considered in any combustion kinetic models so far.Due to the intrinsic multi-reference nature of their transition states,the energy barriers for the two reactions are determined using the CASPT2/aug-cc-pVTZ method with the active space of(7e,7o),and CASPT2/cc-pVDZ method with the active space of(14e,12o),respectively,based on the optimized geometries and rovibrational properties obtained at M06-2X/6-311++G(d,p)level of theory.The rate constants for the two reactions in the temperature range 298.15—2000 K are calculated by using transition state theory.By incorporating these two reaction pathways with our calculated rate constants into a NH3/CH4 kinetic model,the predicted lowtemperature ignition delay times(IDT)of NH3/CH4 mixtures become noticeably shorter.
摘要The electromagnetic shift of energy levels of H-atom electrons is determined by calculating an electron coupling to the Gibbons-Hawking ectromagnetic field thermal bath. Energy shift of electrons in H-atom is determined in the framework of non-relativistic quantum mechanics.
摘要Based on recent advances in attosecond strong-field spectroscopy and the current feasibility for trapping individual groundstate H-atoms from a neon-gas matrix, an experiment to probe the groundstate motion of the electron in the H-atom is proposed here.
摘要近年来,直接光激发芳酮介导的氢原子转移反应在有机合成领域受到一定关注。芳酮可在光激发后通过氢原子转移(Hydrogen Atom Transfer,HAT)过程活化底物中的C(sp3)-H键,生成相应的自由基中间体。将该类催化剂与电化学手段相结合,构建电光催化体系,可在无外加氧化剂和金属试剂的温和条件下实现多种惰性化学键的转化。综述了该领域的研究进展,重点介绍了利用芳酮的双重催化功能实现的几类反应,包括杂芳烃的C(sp2)-H烷基化、酰基化、硅基化环化及硼化反应。这些研究通过从甲酰胺、醛、有机硅烷及硼烷络合物等前体中直接生成酰基、磷酰基、硅基及硼基自由基,为含氮杂环及羰基化合物的高效合成提供了多样化选择的途径。