The Electronic Structure of Short Carbon Nanotubes: The Effects of Correlation

Table 2

CAS-CI and the NEVPT2 energies in kJ mol⁻¹ for the class of nanotubes , with even and even. All possible states for a CAS of two electrons in two orbitals have been calculated.

n∖p	State	2		4		6		8
		CAS-CI	NEVPT2	CAS-CI	NEVPT2	CAS-CI	NEVPT2	CAS-CI	NEVPT2
6		5  ⋅	−19.5	3  ⋅	−5.9	6  ⋅	−2.4	3  ⋅	−1.1
		0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
		419.8	150.8	511.9	159.2	553.2	179.9	579.0	251.7
8		3  ⋅	−34.7	1  ⋅	−22.3	8  ⋅	−20.9	1  ⋅	−24.3
		0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0
		316.3	110.8	395.5	74.9	439.6	−115.0	456.9	−553.8
10		7  ⋅	−56.9	4  ⋅	−63.5	4  ⋅	−98.1	—	—
		0.0	0.0	0.0	0.0	0.0	0.0	—	—
		251.7	84.9	319.9	−60.1	354.7	−390.8	—	—