Molecular Modeling and Spectroscopic Studies of Benzothiazole

Table 5

Second-order perturbation energies 𝐸(2) (donor → acceptor) for benzothiazole.

Donor (𝑖)	Acceptor (𝑗)	E(2) (kJ mol^−1)^a	E(j) − E(i)^b (a. u.)	F (i, j)^c (a. u.)
Within unit 1
LP (1) S1	𝜎^∗C2–N3	1.50	1.70	0.045
LP (1) S1	𝜋^∗C2–N3	1.38	1.05	0.035
LP (1) S1	𝜎^∗C4–C5	1.77	1.61	0.048
LP (1) S1	𝜎^∗C5–C9	0.52	1.64	0.026
LP (2) S1	𝜋^∗C2–N3	8.98	0.59	0.065
LP (2) S1	𝜎^∗C2–H10	1.41	1.09	0.036
LP (2) S1	𝜎^∗C4–C5	1.21	1.14	0.034
LP (2) S1	𝜎^∗C5–C9	1.98	1.18	0.044
LP (1) N3	𝜎^∗C2–N6	2.64	1.17	0.050
LP (1) N3	𝜎^∗C4–C5	9.23	1.38	0.102
LP (1) N3	𝜎^∗C4–H7	3.47	1.25	0.060
LP (1) N3	𝜎^∗S1–C2	27.32	0.77	0.130
LP (1) N3	𝜎^∗C4–C6	0.85	1.35	0.031
LP (1) N3	𝜎^∗C4–C6	1.17	0.70	0.027

aE(2) means energy of hyper conjugative interaction (stabilization energy).
bEnergy difference between donor and acceptor i and j NBO orbitals.
cF (i, j) is the Fock matrix element between i and j NBO orbitals.