Seminar

[Crotta Eleonora]

SEMINAR

Tuesday, 17 October 2006
11:00 hrs, MB SEMINAR ROOM

Mama NSANGOU
University of Ngaoundere
CAMEROON

"Theoretical Investigations of the Stability and Metastabilty of NCCN-: 
Ab initio Studies"

ABSTRACT
Large ab initio calculations have been performed for both the neutral 
cyanogen (NCCN) and its negatively charged ion  (NCCN -), allowing 
predicting a positive electron affinity (EA) for this species of  about 
0.25 ± 0.05 eV. At the Coupled Cluster level of theory, the anion is 
found possessing a trans bent structure where the CN (CC) stretch is 
computed 1.203 Å(1.436 Å) and in-plane angles of 151° with a small 
potential  barrier to linearity (of 1500 cm-1). Interaction 
configuration computations dealing with the NCCN triplets and NCCN - 
quartets reveal that the lowest a4Bu state is lying energetically below 
its corresponding triplet parent state (i.e. d3Bg). However, fast 
electron loss processes are expected to occur for non-planar 
configurations (in the C1 point group) either directly or after 
vibronic and/or spin-orbit couplings with the lower lying electronic 
states, reducing the lifetimes of the rovibronic levels of this 
quartet, as well as those of the other quartets and electronically 
excited doublet states of NCCN -.