DFT and AM1 methods were used to study the reaction of OH radical with hexachlorobenzene(HCB). The optimized structures of the reactants, the products and the transition states were found. A reasonable reaction path w...DFT and AM1 methods were used to study the reaction of OH radical with hexachlorobenzene(HCB). The optimized structures of the reactants, the products and the transition states were found. A reasonable reaction path was determined through IRC calculations. The activation energy obtained is in good agreement to the experimental value.展开更多
The mechanisms of the CH2＋ O2→ H2O＋ CO and CH2＋ O2→ H2＋ CO2 reactions have been studied by performing ab initio CAS(8,8)/6-31G(d,p) calculations, and five intermediates(IMn) and eight transitions(TSn) have been ...The mechanisms of the CH2＋ O2→ H2O＋ CO and CH2＋ O2→ H2＋ CO2 reactions have been studied by performing ab initio CAS(8,8)/6-31G(d,p) calculations, and five intermediates(IMn) and eight transitions(TSn) have been located along the reaction paths. The predicted path for the CH2＋ O2→ H2O＋ CO is: CH2＋ O2→ TS1→ IM1→ TS2→ IM2→ TS3→ IM3→ TS4→ IM4a→ TS5→ H2O＋ CO. For the CH2＋ O2→ H2＋ CO2 reaction, there are two paths: (i) CH2＋ O2→ TS1→ IM1→ TS2→ IM2→ TS3→ IM3→ TS6→ H2＋ CO2 and (ii) CH2＋ O2→ TS1→ IM1→ TS2→ IM2→ TS3→ IM3→ TS4→ IM4a→ TS7→ IM4b→ TS8→ H2＋ CO2, with the latter path more favorable energetically.展开更多
The DPT B3LYP calculations predict isotropic proton hyperfine coupling constant A (H) value of 127. 4 MHz for the HCS radical, in excellent agreement with the recently reported ex- perimental value of 127.427 MHz. The...The DPT B3LYP calculations predict isotropic proton hyperfine coupling constant A (H) value of 127. 4 MHz for the HCS radical, in excellent agreement with the recently reported ex- perimental value of 127.427 MHz. The B3LYP calculations confirm the experimental fact that the A (H) value of HCS is much smaller than the A (H) values of HCO, HSiS, and HSiO, for which we present a simple explanation on the basis of the analysis of spin densities.展开更多
The Jahn Teller distorted states, 2 B 2g and 2 B 1g of the benzene radical cation have been studied by using ab initio MPn and SDCI methods. The calculations indicate that 2 B 2g is the ground state of the benzene cat...The Jahn Teller distorted states, 2 B 2g and 2 B 1g of the benzene radical cation have been studied by using ab initio MPn and SDCI methods. The calculations indicate that 2 B 2g is the ground state of the benzene cation and that 2 B 1g is higher in energy than 2 B 2g and represents a saddle point. The calculated isotropic and anisotropic hyperfine coupling constants for the 2 B 2g state are in excellent agreement with those obtained from the ESR experiments. It is concluded that the benzene cation is in the 2 B 2g Jahn Teller distorted state.展开更多
文摘DFT and AM1 methods were used to study the reaction of OH radical with hexachlorobenzene(HCB). The optimized structures of the reactants, the products and the transition states were found. A reasonable reaction path was determined through IRC calculations. The activation energy obtained is in good agreement to the experimental value.
文摘The mechanisms of the CH2＋ O2→ H2O＋ CO and CH2＋ O2→ H2＋ CO2 reactions have been studied by performing ab initio CAS(8,8)/6-31G(d,p) calculations, and five intermediates(IMn) and eight transitions(TSn) have been located along the reaction paths. The predicted path for the CH2＋ O2→ H2O＋ CO is: CH2＋ O2→ TS1→ IM1→ TS2→ IM2→ TS3→ IM3→ TS4→ IM4a→ TS5→ H2O＋ CO. For the CH2＋ O2→ H2＋ CO2 reaction, there are two paths: (i) CH2＋ O2→ TS1→ IM1→ TS2→ IM2→ TS3→ IM3→ TS6→ H2＋ CO2 and (ii) CH2＋ O2→ TS1→ IM1→ TS2→ IM2→ TS3→ IM3→ TS4→ IM4a→ TS7→ IM4b→ TS8→ H2＋ CO2, with the latter path more favorable energetically.
文摘The DPT B3LYP calculations predict isotropic proton hyperfine coupling constant A (H) value of 127. 4 MHz for the HCS radical, in excellent agreement with the recently reported ex- perimental value of 127.427 MHz. The B3LYP calculations confirm the experimental fact that the A (H) value of HCS is much smaller than the A (H) values of HCO, HSiS, and HSiO, for which we present a simple explanation on the basis of the analysis of spin densities.
文摘The Jahn Teller distorted states, 2 B 2g and 2 B 1g of the benzene radical cation have been studied by using ab initio MPn and SDCI methods. The calculations indicate that 2 B 2g is the ground state of the benzene cation and that 2 B 1g is higher in energy than 2 B 2g and represents a saddle point. The calculated isotropic and anisotropic hyperfine coupling constants for the 2 B 2g state are in excellent agreement with those obtained from the ESR experiments. It is concluded that the benzene cation is in the 2 B 2g Jahn Teller distorted state.
