Department of Chemical Physics, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
J Chem Phys. 2010 Jun 28;132(24):244309. doi: 10.1063/1.3457945.
The predissociation dynamics of nitrous oxide ion (N(2)O(+)) at its first excited state A (2)Sigma(+) has been investigated with ion velocity imaging by probing the NO(+) fragments. The parent ion N(2)O(+), prepared at the ground state X (2)Pi(000) through (3+1) resonance-enhanced multiphoton ionization (REMPI) of jet-cooled N(2)O molecules at 360.55 nm, was excited to different vibrational levels of the A (2)Sigma(+) state in a wavelength range of 280-320 nm, and then predissociated to form NO(+) and N fragments. The internal energy distribution of the NO(+) fragment was determined from its ion velocity images. With the help of potential energy surfaces (PESs) of N(2)O(+), three dissociation pathways have been proposed to interpret the three kinds of NO(+) fragments with different internal state distributions: (1) the A (2)Sigma(+) state couples to a dissociative 1 (4)Sigma(-) state via a bound 1 (4)Pi state to form the NO(+)+N((4)S) channel, where NO(+) fragment is rotationally hot; (2) the A (2)Sigma(+) state couples to dissociative states (2)Sigma(-)/(2)Delta via the 1 (4)Pi state to form the NO(+)+N((2)D) channel, where NO(+) fragment is also rotationally hot; (3) the A (2)Sigma(+) state couples to the high energy region of the ground state X (2)Pi and then dissociates to form the NO(+)+N((2)D) channel, where NO(+) is rotationally cold.
一氧化二氮离子（N(2)O(+)) 在其第一激发态 A (2)Sigma(+) 的预解离动力学已通过探测 NO(+) 碎片用离子速度成像进行了研究。母体离子 N(2)O(+) 通过在 360.55nm 处用射流冷却的 N(2)O 分子的（3+1）共振增强多光子电离（REMPI）制备，处于基态 X (2)Pi(000)，被激发到 A (2)Sigma(+) 态的不同振动能级，波长范围为 280-320nm，然后预解离形成 NO(+) 和 N 碎片。通过其离子速度图像确定了 NO(+) 碎片的内部能量分布。借助 N(2)O(+) 的势能面（PES），提出了三种解离途径来解释具有不同内部状态分布的三种类型的 NO(+) 碎片：（1）A (2)Sigma(+) 态通过束缚态 1 (4)Pi 态与离解态 1 (4)Sigma(-) 耦合，形成 NO(+)+N((4)S) 通道，其中 NO(+) 碎片具有旋转热；（2）A (2)Sigma(+) 态通过 1 (4)Pi 态与离解态（2)Sigma(-)/(2)Delta 耦合，形成 NO(+)+N((2)D) 通道，其中 NO(+) 碎片也具有旋转热；（3）A (2)Sigma(+) 态与基态 X (2)Pi 的高能区域耦合，然后解离形成 NO(+)+N((2)D) 通道，其中 NO(+) 是旋转冷的。
