中文摘要：

用一束波长为360.55 nm的激光直接作用于超声射流的N2O分子束,通过（3＋1）共振增强多光子电离（REMPI）过程制备纯净的N2O＋（X^2Π（0,0,0））母体离子,再用另一束波长在243-278 nm范围的激光将母体离子激发至B^2Π态后解离.扫描解离激光波长,监测NO^＋离子碎片的强度,从而获得N2O＋离子B^2Π态的光致碎片激发（PHOFEX）谱.通过拟合转动分辨光谱,得到了相应的转动常数和自旋分裂常数,从而区分了A^2Σ^＋态高振动能级和B^2Π态带源的贡献,明确了N2O＋离子B^2Π态的光谱＂带头＂位置（37154 cm-1）,并将获得的振动光谱初步归属为B^2Π（v1,v2,v3）←X^2Π的振动跃迁序列.通过对NO^＋碎片离子的飞行时间质谱峰形的分析,还获得了解离过程中释放的平均平动能,并结合电子激发态势能面,讨论了N2O＋离子B^2Π态的解离机理.

英文摘要：

N2O＋ions in the X^2Π（0,0,0） ground state were prepared by（3＋1） resonance-enhanced multiphoton ionization（REMPI） of jet-cooled N2 O molecules at 360.55 nm, and then photoexcited to various vibrational levels in the B^2Π state over a wavelength range of 243-278 nm, followed by dissociation. The photofragment excitation（PHOFEX） spectrum was recorded by measuring the intensity of NO^＋ ion fragments vs excitation wavelength.The rotational constants and spin-orbit coupling were obtained by fitting the rotational structures of the vibrational bands. Thus, the contributions of highly excited vibronic levels of A^2Σ^＋ states were distinguished from the other bands, and the original band of B^2Π state was verified. The series of vibrational bands in the PHOFEX spectrum were assigned to the transition of B^2Π（v1,v2,v3） ←X^2Π. The average released kinetic energy of dissociation from the various B^2Π（v1,v2,v3） ionic states was obtained by fitting the spreading contour of the NO^＋ion peak in time-of-flight mass spectra. Dissociation mechanisms of N2O＋（B^2Π） were proposed with the aid of the theoretical potential energy surfaces of N2O＋ions.