CAJ | 학술논문

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+(X2Π(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B2Π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B2Π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A2Σ+态高振动能级和B2Π态带源的贡献,明确了N2O+离子B2Π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B2Π(v1,v2,v3)←X2Π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B2Π态的解离机理.
용일속파장위360.55 nm적격광직접작용우초성사류적N2O분자속,통과(3+1)공진증강다광자전리(REMPI)과정제비순정적N2O+(X2Π(0,0,0))모체리자,재용령일속파장재243-278 nm범위적격광장모체리자격발지B2Π태후해리.소묘해리격광파장,감측NO+리자쇄편적강도,종이획득N2O+리자B2Π태적광치쇄편격발(PHOFEX)보.통과의합전동분변광보,득도료상응적전동상수화자선분렬상수,종이구분료A2Σ+태고진동능급화B2Π태대원적공헌,명학료N2O+리자B2Π태적광보“대두”위치(37154 cm-1),병장획득적진동광보초보귀속위B2Π(v1,v2,v3)←X2Π적진동약천서렬.통과대NO+쇄편리자적비행시간질보봉형적분석,환획득료해리과정중석방적평균평동능,병결합전자격발태세능면,토론료N2O+리자B2Π태적해리궤리.
N2O+ions in the X2Π(0,0,0) ground state were prepared by (3+1) resonance-enhanced multiphoton ionization (REMPI) of jet-cooled N2O molecules at 360.55 nm, and then photoexcited to various vibrational levels in the B2Πstate over a wavelength range of 243-278 nm, fol owed 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 A2Σ+states were distinguished from the other bands, and the original band of B2Πstate was verified. The series of vibrational bands in the PHOFEX spectrum were assigned to the transition of B2Π(v1,v2,v3)←X2Π. The average released kinetic energy of dissociation from the various B2Π(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+(B2Π) were proposed with the aid of the theoretical potential energy surfaces of N2O+ions.