Real-time dynamics of ammonia clusters excited through the (A)over-tilde state: Formation of the protonated cluster ions

被引：34

作者：

Snyder, EM ^{[1
]}

Purnell, J ^{[1
]}

Wei, S ^{[1
]}

Buzza, SA ^{[1
]}

Castleman, AW ^{[1
]}

机构：

[1] PENN STATE UNIV,DEPT CHEM,UNIVERSITY PK,PA 16802

来源：

CHEMICAL PHYSICS | 1996年 / 207卷 / 2-3期

关键词：

D O I：

10.1016/0301-0104(95)00402-5

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Femtosecond pump-probe techniques combined with a reflectron time-of-flight mass spectrometer are employed to study the dynamics of ammonia clusters excited to the A state. In this paper we present data on the formation of protonated ammonia cluster ions and consider a reaction scheme for their formation through the dissociation of (NH3)(n) ((A) over tilde(1)A ''(2)). We propose that the formation of the radical (NH3)(n-2)NH4 species is due to a reaction involving the dissociation of (NH3)(n) ((A) over tilde(1)A ''(2)) to NH2 ((A) over tilde(2)A(1)). A competing process in the dissociation of (NH3)(n) ((A) over tilde(1)A ''(2)) to NH2 ((X) over tilde(2)B(1)), yields fragments that are too translationally ''hot'' to react to form the (NH3)(n-2)NH4 species. We also quantitatively model these reactions and report the lifetimes associated with the dissociation processes of (NH3)(n), and concomitant formation of (NH3)(n-2)NH4. Lifetimes of 250-900 fs are observed for the dissociation of (NH3)(3-23) excited to the (A) over tilde state.

引用

页码：355 / 366

页数：12

共 39 条

[1] PHOTODISSOCIATION OF AMMONIA IN A]-X ABSORPTION SYSTEM .2. TRANSLATIONAL EXCITATION OF HYDROGEN-ATOMS PRODUCED, AND MECHANISM OF PREDISSOCIATION [J].