Potential energy surfaces(PESs), vibrational frequencies, and infrared spectra are calculated for NF_(3)^(+) using ab initio calculations, based on UCCSD(T)/cc-p VTZ combined with vibrational configuration interaction...Potential energy surfaces(PESs), vibrational frequencies, and infrared spectra are calculated for NF_(3)^(+) using ab initio calculations, based on UCCSD(T)/cc-p VTZ combined with vibrational configuration interaction(VCI). Based on an iterative algorithm, the surfaces(SURF) program adds automatic points to the lattice representation of the potential function, the one-dimensional and two-dimensional PESs are calculated after reaching a convergence threshold, finally the smooth image of the potential energy surface is fitted. The PESs accurately account for the interaction between the different modes, with the mode q_(6) symmetrical stretching vibrations having the greatest effect on the potential energy change of the whole system throughout the potential energy surface shift. The anharmonic frequencies are obtained when the VCI matrix is diagonalized. Fundamental frequencies, overtones, and combination bands of NF_(3)^(+) are calculated, which generate the degenerate phenomenon between their frequencies. Finally, the calculated anharmonic frequency is used to plot the infrared spectra.Modal antisymmetric stretching ν_(5) and symmetric stretching ν_(6) exhibit a phenomenon of large-intensity borrowing. This study can provide data to support the characterization in the laboratory.展开更多
CBA反应器是美国BV公司四级转化冷床吸附(Cold Bed Adsorption,以下简称CBA)工艺中的重要设备。在重庆天然气净化总厂引进分厂CBA装置各级反应器人孔处多次出现耐火衬里垮塌、催化剂泄漏,引起液硫管线堵塞,从而造成多次临停事故。针对...CBA反应器是美国BV公司四级转化冷床吸附(Cold Bed Adsorption,以下简称CBA)工艺中的重要设备。在重庆天然气净化总厂引进分厂CBA装置各级反应器人孔处多次出现耐火衬里垮塌、催化剂泄漏,引起液硫管线堵塞,从而造成多次临停事故。针对这一问题,对该处衬里垮塌分别从工艺和设备两方面的原因进行了分析。最后从工艺方面提出了低负荷运行时加燃料气与酸气混烧以提高反应器温度的改造方案,从设备方面提出了对人孔附近保温结构、本体结构、衬里结构等多方面进行改进的改造方案,经过上述技术改造后效果明显。展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.52002318 and 22103061)。
文摘Potential energy surfaces(PESs), vibrational frequencies, and infrared spectra are calculated for NF_(3)^(+) using ab initio calculations, based on UCCSD(T)/cc-p VTZ combined with vibrational configuration interaction(VCI). Based on an iterative algorithm, the surfaces(SURF) program adds automatic points to the lattice representation of the potential function, the one-dimensional and two-dimensional PESs are calculated after reaching a convergence threshold, finally the smooth image of the potential energy surface is fitted. The PESs accurately account for the interaction between the different modes, with the mode q_(6) symmetrical stretching vibrations having the greatest effect on the potential energy change of the whole system throughout the potential energy surface shift. The anharmonic frequencies are obtained when the VCI matrix is diagonalized. Fundamental frequencies, overtones, and combination bands of NF_(3)^(+) are calculated, which generate the degenerate phenomenon between their frequencies. Finally, the calculated anharmonic frequency is used to plot the infrared spectra.Modal antisymmetric stretching ν_(5) and symmetric stretching ν_(6) exhibit a phenomenon of large-intensity borrowing. This study can provide data to support the characterization in the laboratory.
文摘CBA反应器是美国BV公司四级转化冷床吸附(Cold Bed Adsorption,以下简称CBA)工艺中的重要设备。在重庆天然气净化总厂引进分厂CBA装置各级反应器人孔处多次出现耐火衬里垮塌、催化剂泄漏,引起液硫管线堵塞,从而造成多次临停事故。针对这一问题,对该处衬里垮塌分别从工艺和设备两方面的原因进行了分析。最后从工艺方面提出了低负荷运行时加燃料气与酸气混烧以提高反应器温度的改造方案,从设备方面提出了对人孔附近保温结构、本体结构、衬里结构等多方面进行改进的改造方案,经过上述技术改造后效果明显。
