Nitrogen

Figure 1. Optimized Geometry from 6-31G Theory

Optimized (lowest energy) bond length using 6-31G theory most closely matched literature values.

Table 1. Calculated Bond Order, Bond Length, and Dipole Moment Data

Theory	Bond Order	Bond Length (Angstroms)	Dipole
6-31G	2.628	1.089	0
6-21G	2.778	1.089	0
AMI	N/A	1.106	0
Literature Val.	3	1.098	0

Figure 2. Highest Occupied Molecular Orbital	3-Dimensional representation of the highest occupied molecular orbital (HOMO). The HOMO-1 is orthogonal (identical and perpendicular) to the HOMO. Both HOMO and HOMO-1 depict pi bonding.
Figure 3. Lowest Unoccupied Molecular Orbital	3-Dimensional representation of the lowest unoccupied molecular orbital (LUMO). The LUMO is an anti-bonding orbital with two orthogonal nodal planes.

Figure 4. Potential Energy Curves for Nitrogen Bond Lengths Created with Igor

The calculation using the 6-311++ theory exhibits the deepest energy well, and is therefore the best fit. 6-311++ has the largest basis set and produces the lowest energy well because it incorporates the most parameters. 6-21G has the smallest basis set and produces the highest energy well.