Table 5.

Computed NBO parameters for some of the important natural bond orbitals in the H-bonding region in D₁.

NBOs Ω/Ω∗ (A-B)	Occupancy q	Polarization coefficients (%)		Description of NBO	Contribution of s character (%)		ΔqΩΩ*
		cA2	cB2		A	B
σ(1C–2O)	1.99575	34.37	65.63	0.5862 (sp2.15)C1 + 0.8101 (sp1.57)O2	31.64	38.86	1.94797
σ∗(1C–2O)	0.04778	65.63	34.37	0.8101 (sp2.15)C1 - 0.5862 (sp1.57)O2
π(1C–2O)	1.98812	23.06	76.94	0.4802 (p)C1 + 0.8772 (p)O2	1.45	0.25	1.63194
π∗(1C–2O)	0.35618	76.94	23.06	0.8772 (p)C1 - 0.4802 (p)O2
σ(1C–3O)	1.98748	32.45	67.55	0.5697 (sp2.20)C1 + 0.8219 (sp2.05)O3	31.15	32.77	1.88137
σ∗(1C–3O)	0.10611	67.55	32.45	0.8219 (sp2.20)C1 - 0.5697 (sp2.05)O3
σ(20N–21H)	1.99045	76.22	23.78	0.8730 (sp2.84)N20 + 0.4877 (s)H21	26.03	99.89	1.90924
σ∗(20N–21H)	0.08121	23.78	76.22	0.4877 (sp2.84)N20 - 0.8730 (s)H21
σ(20N–22H)	1.99275	72.06	27.94	0.8489 (sp3.50)N20 + 0.5286 (s)H22	22.19	99.94	1.98324
σ∗(20N–22H)	0.00951	27.94	72.06	0.5286 (sp3.50)N20 - 0.8489 (s)H22
σ(20N–32H)	1.99277	72.07	27.93	0.8489 (sp3.55)N20 + 0.5285 (s)H32	21.96	99.94	1.98385
σ∗(20N–32H)	0.00892	27.93	72.07	0.5285 (sp3.55)N20 - 0.8489 (s)H32
n1(2O)	1.97908			sp0.64	60.93
n2(2O)	1.90125			p	0.01
n1(3O)	1.96243			sp0.82	54.98
n2(3O)	1.86544			p	7.70
n3(3O)	1.61485			p	4.56

Note: Δq_ΩΩ* = Difference in occupancies q_Ω – q_Ω*. Where Ω - bonding and Ω^∗ - antibonding orbitals on A and B.