Search

Using highly correlated wave functions, the ground and the low lying excited states of the molecular NCO- and CNO- anions have been reinvestigated. The stability of the electronic ground state of the two isomers with respect to dissociation and to electron detachment has been checked along the isomerization pathway. The regions of stability of the excited electronic states have been analyzed and identified and it is shown that only the ground state is stable and the corresponding potential energy surface presents three equilibrium positions. The rovibronic spectroscopy of the X 1Σ+ state of both NCO- and CNO- isomers has been determined by a variational approach leading to remarkable agreement with experimental data. [ABSTRACT FROM AUTHOR]

Using highly correlated wave functions, the ground and the low lying excited states of the molecular NCO- and CNO- anions have been reinvestigated. The stability of the electronic ground state of the two isomers with respect to dissociation and to electron detachment has been checked along the isomerization pathway. The regions of stability of the excited electronic states have been analyzed and identified and it is shown that only the ground state is stable and the corresponding potential energy surface presents three equilibrium positions. The rovibronic spectroscopy of the X 1Σ+ state of both NCO- and CNO- isomers has been determined by a variational approach leading to remarkable agreement with experimental data. [ABSTRACT FROM AUTHOR]

Highly correlatedab initiowave functions within the UCCSD(T)-F12 approach have been used to map portions of the potential energy surfaces and to study the stability of the first excited triplet states of the NCS−/CNS−and NCO−/CNO−anions. Thesea3Π states for linear geometries, or their3A′ and3A″ bent components, correlate with the lowest dissociation asymptote of NCX−(X = S and O) along the NC-X coordinates. TheX1Σ+linear ground states of these anions are known to be stable with respect to dissociation to theX2Π ground state of the corresponding neutral molecule with a rather large electron affinity. Thea3Π state of the NCS−anion is positioned below theXstate 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 theXstate 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. [ABSTRACT FROM PUBLISHER]

The potential energy surfaces (PESs) for several electronic states involved in the reaction O[sup +] ([sup 4] S) + N[sub 2] (X[sup 1] Σ[sup +] ) → NO[sup +] (X[sup 1] Σ[sup +] , υ′) + N([sup 4] S) and the role of the ionic N[sub 2] O[sup +] intermediate have been investigated by ab initiocalculations. The [sup 4] A″ PES, which correlates with the ground state educts, has a barrier of about 1eV, and therefore at low collision energies the reaction cannot take place adiabatically on this surface. However, the spin-orbit coupling in the entrance channel allows the system to pass into the Renner-Teller system of the X[sup 2] Π electronic ground state of the N[sub 2] O[sup +] intermediate. The reaction then proceeds on these surfaces up to the region in the exit channel where a similar coupling allows it to reach the product quartet asymptote. At collision energies higher than about 1eV, the reaction proceeds mainly on the adiabatic PES of the [sup 4] A″ state. The A[sup 2] Σ[sup +] state of N[sub 2] O[sup +] predissociates via a vibronic coupling with the B[sup 2] Π state, and in bent structures via a spin-orbit coupling with the 4A component of the [sup 4] Π state. The electronic structure of the B[sup 2] Π state is found to be of crucial importance for the understanding of the reactive processes in low lying electronic states of N[sub 2] O[sup +] . [ABSTRACT FROM AUTHOR]