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

Table 1

The various ground state energy levels and their occupation numbers (STO-3G basis set) for the four different classes of nanotubes along with their true symmetries. It is interesting to note the abelian groups of each class: class I ; class II ; class III ; class IV .

Nanotube	Symmetry group of the nanotube	Orbitals symmetry	High-spin ROHF orbital energy	Electronic ground state		CAS-CI occupation number
			in au	HF	CAS-CI
		(i)	−0.1180			1.0000
		(ii)
		(i)	−0.1176			0.9985
		(ii)	−0.1178			1.0015
		(i)	−0.1359			0.9517
		(ii)
		(iii)	−0.1431			1.0483
		(iv)
		(i)	−0.1384			0.9684
		(ii)
		(iii)	−0.1417			1.0316
		(iv)