Nitrogen potential energy curve

Fig. 6. Potential energy curve relative to the interconversion between ionic and covalent structure for the NHs-HCl complex (NH3 + HCl —> NH4 + C ). dNH represents the distance between the ammonia molecule nitrogen and the hydrogen of the HCl fragment involved in hydrogen bond along the axis (dNH ci HCi)- TZVP standard basis was employed. Energies and distances are in a.u.

In the nitrogen molecule, we found no significant difference in the CT energies between using NOs and canonical CAS orbitals over the potential curve, unlike in the H2O case. However, it is still important to optimize the orbitals, as the CASCI-based L-CTD does not yield a correct potential curve. Finally, as in the water calculations, the L-CTSD(2) approximation recovers most of L-CTSD correlation energy across the potential energy curve. 

The potential energy curve for the nitrogen inversion process in NX 3 is a symmetrical double minimum curve with an energy barrier Fmax (Fig. 1). 

Fig. 2. The calculated [D-MBPT(4)] potential energy curves for the three lowest electronic states of nitrosyl hydride. For each choice of R j shown, the bond angle and nitrogen-oxygen bond length were optimized for each of the states.

Figure 6.1 Schematic potential energy diagram for atomic and molecular nitrogen adsorption on a clean and K-covered Fe(100) surface. Curve (a) is for N2 + Fe(100) curve (b) is for N2 + Fe(100)-K. Note the lowering of the activation energy for dissociation from 3 kcalmol-1 to zero. (Reproduced from Ref. 3).

Figure 1. The shape of the potential curve for nitrogen in a correlation-consistent polarized double-zeta basis set is presented for the variational 2-RDM method as well as (a) single-reference coupled cluster, (b) multireference second-order perturbation theory (MRPT) and single-double configuration interaction (MRCl), and full configuration interaction (FCl) wavefunction methods. The symbol 2-RDM indicates that the potential curve was shifted by the difference between the 2-RDM and CCSD(T) energies at equilibrium.

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