Institute for Scientific Research, 22 Bonad Road, Winchester, Massachusetts 01890, USA.
J Chem Phys. 2012 Aug 21;137(7):074309. doi: 10.1063/1.4739472.
Comprehensive theoretical calculations are reported for the dissociative recombination of the lowest vibrational level of the N(2)(+) ground state. Fourteen dissociative channels, 21 electron capture channels, and 48 Rydberg series including Rydberg states having the first excited state of the ion as core are described for electron energies up to 1.0 eV. The calculation of potential curves, electron capture and predissociation widths, cross sections and rate constants are described. The cross sections and rate constants are calculated using Multichannel Quantum Defect Theory which allows for efficient handling of the Rydberg series. The most important dissociative channel is 2(3)Π(u) followed by 4(3)Π(u). Dissociative states that do not cross the ion within the ground vibrational level turning points play a significant role in determining the cross section structure and at isolated energies can be more important than states having a favorable crossing. By accounting for autoionization, the interactions between resonances, between dissociative states, and between resonances and dissociative states it is found that the cross section can be viewed as a complex dissociative recombination spectrum in which resonances overlap and interfere. The detailed cross section exhibits a rapid variation in atomic quantum yields for small changes in the electron energy. A study of this rapid variation by future high resolution storage ring experiments is suggested. A least squares fit to the calculated rate constant from the ground vibrational level is 2.2(+0.2)/(-0.4) × 10(-7) × (T(e)/300)(-0.40) cm(3)/sec for electron temperatures, T(e), between 100 and 3000 K and is in excellent agreement with experimentally derived values.
全面的理论计算报告了 N(2)(+)基态最低振动能级的解离复合。在电子能量高达 1.0 eV 的情况下，描述了 14 个解离通道、21 个电子俘获通道和 48 个里德堡系列，包括以离子的第一激发态为核的里德堡态。描述了势曲线、电子俘获和预解离宽度、截面和速率常数的计算。截面和速率常数是使用多通道量子亏损理论计算的，该理论允许有效地处理里德堡系列。最重要的解离通道是 2(3)Π(u)，其次是 4(3)Π(u)。在基态振动能级转折点内不与离子交叉的解离态在确定截面结构方面起着重要作用，在孤立能量下，它们可能比具有有利交叉的态更为重要。通过考虑自电离，共振之间、解离态之间以及共振和解离态之间的相互作用，发现截面可以看作是一个复杂的解离复合光谱，其中共振重叠和干扰。详细的截面在电子能量的微小变化下表现出原子量子产率的快速变化。建议未来的高分辨率存储环实验对这种快速变化进行研究。从基态振动能级计算得到的速率常数的最小二乘拟合为 2.2(+0.2)/(-0.4) × 10(-7) × (T(e)/300)(-0.40) cm(3)/sec，其中 T(e)为 100 到 3000 K 之间的电子温度，与实验得出的值非常吻合。
