Are there Stable Excited Triplet States of NCS-/CNS- and NCO-/CNO-?

D. Khiri (1, 2) , H. Gritli (1) , K. Peterson (3) , Gilberte Chambaud (2)

1 LSAMA - Laboratoire de Spectroscopie Atomique, Moléculaire et Applications
2 MSME - Laboratoire de Modélisation et Simulation Multi Echelle
3 WSU - Washington State University

Highly correlated ab initio wave functions within the UCCSD(T)-F12 approach have been used to map portions of the potential energy surfaces (PESs) and to study the stability of the first excited triplet states of the NCS-/CNS- and NCO-/CNO- anions. These a3Π states for linear geometries, or their 3A' and 3A" bent components, correlate with the lowest dissociation asymptote of NCX- (X = S and O) along the NC-X coordinates. The X1Σ+ linear ground states of these anions are known to be stable with respect to dissociation to the X2Π ground state of the corresponding neutral molecule with a rather large electron affinity (EA). The a3Π state of the NCS- anion is positioned below the X state of the neutral at long NC-S distances and its minimum of energy is found for bent geometries. The stability of its two components in bent geometries has been investigated, and it is found that some anionic forms are stable with respect to the X state of the neutral. The linear CNS- and CNO- isomers present a minimum only at long CN-X distances, located below the minimum of their corresponding neutral CNX ground states.

Mots clés: Potential energy functions; excited states; Molecular anions

Domaines: Chimie théorique et/ou physique

D. Khiri, H. Gritli, K. Peterson, Gilberte Chambaud. Are there Stable Excited Triplet States of NCS-/CNS- and NCO-/CNO-?. Molecular Physics, 2015, 113 (13-14), pp.1534-1540. ⟨10.1080/00268976.2014.981606⟩. ⟨hal-01078896⟩