为了探讨复合物中分子间相互作用对单体分子动力学的影响,对CF3Cl-CO复合物中单体振动谱带基线平移进行了预测。首先,采用二阶多体微扰理论(M?ller-Plesset perturbation theory of second order, MP2)结合扩展相关一致性极化价三重ζ基...为了探讨复合物中分子间相互作用对单体分子动力学的影响,对CF3Cl-CO复合物中单体振动谱带基线平移进行了预测。首先,采用二阶多体微扰理论(M?ller-Plesset perturbation theory of second order, MP2)结合扩展相关一致性极化价三重ζ基组(augmented correlation-consistent polarized valence triple-zeta, Aug-cc-pVTZ)对该复合物的5种结构(S1′、S2、S3、S4、A)进行几何优化、频率计算;然后,引入键函数(3s3p2d1f),在包含单激发、双激发和微扰三激发的耦合簇(coupled cluster with single, double, and perturbative triple excitations, CCSD(T))方法结合Aug-cc-pVTZ的水平上计算稳定结构的分子间相互作用能,并对最稳定结构的单体谱带基线平移进行预测。结果表明,S1′为该复合物的最稳定结构,其分子间相互作用能为-3.81 kJ/mol,其能量分解中交换能占比最高为38%。此外,研究中发现了复合物的2个新的稳定结构S4、A,其分子间相互作用能分别为-2.68、-2.72 kJ/mol。单体谱带基线平移预测表明,在S1′结构中,相比于自由单体振动,复合物中CF3Cl单体的C-Cl键伸缩振动发生了红移,而CO的伸缩振动则表现为蓝移,这表明分子间卤键对分子内动力学存在显著影响。该研究结果为进一步实验测量CF3Cl-CO复合物光谱提供了理论参考。展开更多
The G3 and CBS-QB3 theoretical methods are employed to study the decomposition of CF3OH into FCFO and HF by water, water dimmer, and ammonia. The decomposition of CF3OH into FCFO and HF is unlikely to occur in the atm...The G3 and CBS-QB3 theoretical methods are employed to study the decomposition of CF3OH into FCFO and HF by water, water dimmer, and ammonia. The decomposition of CF3OH into FCFO and HF is unlikely to occur in the atmosphere due to the high activated energy of 88.7 k J/mol at the G3 level of theory. However, the computed results predict that the barrier for unimolecular decomposition of CF3OH is decreased to 25.1 kJ/mol from 188.7 k J/mol with the aid of NH3 at the G3 level of theory, which shows that the ammonia play a strong catalytic effect on the split of CF3OH. In addition, the calculated rate constants show that the decomposition of CF3OH by NH3 is faster than those of H2O and the water dimmer by 10^9 and 10^5 times respectively. The rate constants combined with the corresponding concentrations of these species demonstrate that the reaction CF3OH with NH3 via TS4 is of great importance for the decomposition of CF3OH in the atmosphere.展开更多
CF3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF6 gas,owing to their excellent insulating performance.This paper attempts to study the CF3I ternary gas m...CF3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF6 gas,owing to their excellent insulating performance.This paper attempts to study the CF3I ternary gas mixtures with c-C4F8 and buffer gases N2 and CO2 by considering dielectric strength from electron transport parameters based on the Boltzmann method and synergistic effect analysis,compared with SF6 gas mixtures.The results confirm that the critical electric field strength of CF3I/c-C4F8/70%CO2 is greater than that of 30%SF6/70%CO2 when the CF3I content is greater than 17%.Moreover,a higher content of c-C4F8 decreases the sensitivity of gas mixtures to an electric field,and this phenomenon is more obvious in CF3I/c-C4F8/CO2 gas mixtures.The synergistic effects for CF3I/c-C4F8/70%N2 were most obvious when the c-C4F8 content was approximately 20%,and for CF3I/c-C4F8/70%CO2 when the c-C4F8 content was approximately 10%.On the basis of this research,CF3I/c-C4F8/70%N2 shows better insulation performance when the c-C4F8 content is in the15%–20%range.For CF3I/c-C4F8/70%CO2,when the c-C4F8 content is in the 10%–15%range,the gas mixtures have excellent performance.Hence,these gas systems might be used as alternative gas mixtures to SF6 in high-voltage equipment.展开更多
CF3I is a potential SF6 alternative gas.In order to study the insulation properties and synergistic effects of CF3I/N2 and CF3I/CO2 gas mixtures,two-term approximate Boltzmann equations were used to obtain the ionizat...CF3I is a potential SF6 alternative gas.In order to study the insulation properties and synergistic effects of CF3I/N2 and CF3I/CO2 gas mixtures,two-term approximate Boltzmann equations were used to obtain the ionization coefficient α,attachment coefficient η and the critical equivalent electrical field strength（E/N）（cr）.The results show that the（E/N）（cr）of CF3I gas at 300 K is 1.2 times that of SF6 gas,and CF3I/N2 and CF3I/CO2 gas mixtures both have synergistic effect occurred.The synergistic effect coefficient of CF3I/CO2 gas mixture was higher than that of CF3I/N2 gas mixture.But the（E/N）（cr）of CF3I/N2 is higher than that of CF3I/CO2 under the same conditions.When the content of CF3I exceeds 20%,the （E/N）（cr） of CF3I/N2 and CF3I/CO2 gas mixture increase linearly with the increasing of CF3I gas content.The breakdown voltage of CF3I/N2 gas mixture is also higher than that of CF3I/CO2 gas mixture in slightly non-uniform electrical field under power frequency voltage,but the synergistic effect coefficients of the two gas mixtures are basically the same.展开更多
文摘为了探讨复合物中分子间相互作用对单体分子动力学的影响,对CF3Cl-CO复合物中单体振动谱带基线平移进行了预测。首先,采用二阶多体微扰理论(M?ller-Plesset perturbation theory of second order, MP2)结合扩展相关一致性极化价三重ζ基组(augmented correlation-consistent polarized valence triple-zeta, Aug-cc-pVTZ)对该复合物的5种结构(S1′、S2、S3、S4、A)进行几何优化、频率计算;然后,引入键函数(3s3p2d1f),在包含单激发、双激发和微扰三激发的耦合簇(coupled cluster with single, double, and perturbative triple excitations, CCSD(T))方法结合Aug-cc-pVTZ的水平上计算稳定结构的分子间相互作用能,并对最稳定结构的单体谱带基线平移进行预测。结果表明,S1′为该复合物的最稳定结构,其分子间相互作用能为-3.81 kJ/mol,其能量分解中交换能占比最高为38%。此外,研究中发现了复合物的2个新的稳定结构S4、A,其分子间相互作用能分别为-2.68、-2.72 kJ/mol。单体谱带基线平移预测表明,在S1′结构中,相比于自由单体振动,复合物中CF3Cl单体的C-Cl键伸缩振动发生了红移,而CO的伸缩振动则表现为蓝移,这表明分子间卤键对分子内动力学存在显著影响。该研究结果为进一步实验测量CF3Cl-CO复合物光谱提供了理论参考。
基金This work was supported by the National Natural Science Foundation of China （No.10865003） and the Guizhou University for Nationalities （2010）. The authors thank professors W. T. Duncan, R. L. Bell, and T. N. Truong or providing the rate program through the internet.
文摘The G3 and CBS-QB3 theoretical methods are employed to study the decomposition of CF3OH into FCFO and HF by water, water dimmer, and ammonia. The decomposition of CF3OH into FCFO and HF is unlikely to occur in the atmosphere due to the high activated energy of 88.7 k J/mol at the G3 level of theory. However, the computed results predict that the barrier for unimolecular decomposition of CF3OH is decreased to 25.1 kJ/mol from 188.7 k J/mol with the aid of NH3 at the G3 level of theory, which shows that the ammonia play a strong catalytic effect on the split of CF3OH. In addition, the calculated rate constants show that the decomposition of CF3OH by NH3 is faster than those of H2O and the water dimmer by 10^9 and 10^5 times respectively. The rate constants combined with the corresponding concentrations of these species demonstrate that the reaction CF3OH with NH3 via TS4 is of great importance for the decomposition of CF3OH in the atmosphere.
基金supported by National Natural Science Foundation of China(No.51337006)。
文摘CF3I gas mixtures have attracted considerable attention as potential environmentally-friendly alternatives to SF6 gas,owing to their excellent insulating performance.This paper attempts to study the CF3I ternary gas mixtures with c-C4F8 and buffer gases N2 and CO2 by considering dielectric strength from electron transport parameters based on the Boltzmann method and synergistic effect analysis,compared with SF6 gas mixtures.The results confirm that the critical electric field strength of CF3I/c-C4F8/70%CO2 is greater than that of 30%SF6/70%CO2 when the CF3I content is greater than 17%.Moreover,a higher content of c-C4F8 decreases the sensitivity of gas mixtures to an electric field,and this phenomenon is more obvious in CF3I/c-C4F8/CO2 gas mixtures.The synergistic effects for CF3I/c-C4F8/70%N2 were most obvious when the c-C4F8 content was approximately 20%,and for CF3I/c-C4F8/70%CO2 when the c-C4F8 content was approximately 10%.On the basis of this research,CF3I/c-C4F8/70%N2 shows better insulation performance when the c-C4F8 content is in the15%–20%range.For CF3I/c-C4F8/70%CO2,when the c-C4F8 content is in the 10%–15%range,the gas mixtures have excellent performance.Hence,these gas systems might be used as alternative gas mixtures to SF6 in high-voltage equipment.
基金supported by National Natural Science Foundation of China (Grant No.51337006)China Postdoctoral Science Foundation (2016M602728)the Science and Technology Project of SGCC ‘Research on SF_6 Alternative Gas for Insulation and Arc Quenching Application’
文摘CF3I is a potential SF6 alternative gas.In order to study the insulation properties and synergistic effects of CF3I/N2 and CF3I/CO2 gas mixtures,two-term approximate Boltzmann equations were used to obtain the ionization coefficient α,attachment coefficient η and the critical equivalent electrical field strength（E/N）（cr）.The results show that the（E/N）（cr）of CF3I gas at 300 K is 1.2 times that of SF6 gas,and CF3I/N2 and CF3I/CO2 gas mixtures both have synergistic effect occurred.The synergistic effect coefficient of CF3I/CO2 gas mixture was higher than that of CF3I/N2 gas mixture.But the（E/N）（cr）of CF3I/N2 is higher than that of CF3I/CO2 under the same conditions.When the content of CF3I exceeds 20%,the （E/N）（cr） of CF3I/N2 and CF3I/CO2 gas mixture increase linearly with the increasing of CF3I gas content.The breakdown voltage of CF3I/N2 gas mixture is also higher than that of CF3I/CO2 gas mixture in slightly non-uniform electrical field under power frequency voltage,but the synergistic effect coefficients of the two gas mixtures are basically the same.
