Controversies and arguments about the origin of plan-etary water have aroused enthusiasm to search for possible chemical sources.Considering the CO_(2)-rich atmospheres of Mars,Venus,and the prebiotic Earth,we propose...Controversies and arguments about the origin of plan-etary water have aroused enthusiasm to search for possible chemical sources.Considering the CO_(2)-rich atmospheres of Mars,Venus,and the prebiotic Earth,we propose that chemical reactions between HOCO^(+)and H_(2)can contribute to the production of H_(2)O on the basis of high-level calculations.As for the reagents,HOCO^(+)can form via the protonation of CO_(2),while H+and H_(2)are from the solar wind or in-terstellar space.Note that one of the reaction path-ways undergoes multiple transition-state complexes and exhibits the roaming-like dynamics feature.More-over,intermolecular proton or hydrogen transfer is a key step in the production of H_(2)O,there-by H-tunneling effect profoundly enhances the reaction rate in a wide range of temperatures or collision energies.展开更多
In this paper, the reaction mechanism of HOCO with its radical has been investigated deeply by density functional theory（DFT）, while the geometries and harmonic vibration frequencies of the reactants, intermediates,...In this paper, the reaction mechanism of HOCO with its radical has been investigated deeply by density functional theory（DFT）, while the geometries and harmonic vibration frequencies of the reactants, intermediates, transition states and products have been calculated at the B3LYP/6-311＋＋G＊＊ level. The CCSD（T）/cc-p VQZ method was used to further calculate the single-point energy of each stationary point along the reaction channel. The result shows that channels（b） and（d） via carbon-carbon intermediates are competing with the ones（e）,（f）,（i） and（l） through carbon-oxygen intermediates, and the six channels are dominant for the title reaction to produce HCOOH and CO2. The result also indicates that the hydrogen abstraction from the HOCO radical can be performed quickly by the self-interaction of HOCO in the absence of other radicals or atoms, which indirectly proves for the first time that the ground-state cis-HOCO radical is not decomposed by the tunneling effect. In addition, the charges of natural population analysis（NPA） and the variation of chemical bonds have been analyzed by the Natural Bond Orbital（NBO） method along with the important reaction path.展开更多
基金supported by the National Natural Sci-ence Foundation of China(Nos.22233004,22003062)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0970000).
文摘Controversies and arguments about the origin of plan-etary water have aroused enthusiasm to search for possible chemical sources.Considering the CO_(2)-rich atmospheres of Mars,Venus,and the prebiotic Earth,we propose that chemical reactions between HOCO^(+)and H_(2)can contribute to the production of H_(2)O on the basis of high-level calculations.As for the reagents,HOCO^(+)can form via the protonation of CO_(2),while H+and H_(2)are from the solar wind or in-terstellar space.Note that one of the reaction path-ways undergoes multiple transition-state complexes and exhibits the roaming-like dynamics feature.More-over,intermolecular proton or hydrogen transfer is a key step in the production of H_(2)O,there-by H-tunneling effect profoundly enhances the reaction rate in a wide range of temperatures or collision energies.
基金supported by the National Natural Science Foundation of China(50673085,20677053)the Basic Research Programs of Qingdao Science and Technology Plan(No.13-1-4-233-jch)
文摘In this paper, the reaction mechanism of HOCO with its radical has been investigated deeply by density functional theory（DFT）, while the geometries and harmonic vibration frequencies of the reactants, intermediates, transition states and products have been calculated at the B3LYP/6-311＋＋G＊＊ level. The CCSD（T）/cc-p VQZ method was used to further calculate the single-point energy of each stationary point along the reaction channel. The result shows that channels（b） and（d） via carbon-carbon intermediates are competing with the ones（e）,（f）,（i） and（l） through carbon-oxygen intermediates, and the six channels are dominant for the title reaction to produce HCOOH and CO2. The result also indicates that the hydrogen abstraction from the HOCO radical can be performed quickly by the self-interaction of HOCO in the absence of other radicals or atoms, which indirectly proves for the first time that the ground-state cis-HOCO radical is not decomposed by the tunneling effect. In addition, the charges of natural population analysis（NPA） and the variation of chemical bonds have been analyzed by the Natural Bond Orbital（NBO） method along with the important reaction path.
