Donor(I) Types of Bond Occupancy Acceptor(J) Types of Bond Occupancy E(2) Kcal/Mol E(i)-E(j)a.u F(i,j) C1-C6 π 1.60800 C2-C3 π* 0.30266 14.39 0.28 0.058     1.60800 C4-C5 π* 0.41175 28.92 0.27 0.079 C2-C3 π 1.71091 C1-C6 π* 0.40060 22.67 0.28 0.073     1.71091 C4-C5 π* 0.41175 14.29 0.27 0.057 C4-C5 π 1.69512 C1-C6 π* 0.40060 13.69 0.28 0.057     1.69512 C2-C3 π* 0.30266 23.73 0.29 0.074 C4-As14 σ 1.93366 As14-O15 σ* 0.20270 6.85 0.69 0.064     1.93366 As14-O17 σ* 0.21155 7.80 0.69 0.068     1.93366 As14-O19 σ* 0.09141 7.32 0.79 0.069 As14-O17 σ 1.96936 As14-O15 σ* 0.20270 6.60 0.80 0.068 As14-O19 σ 1.95966 As14-O17 σ* 0.21155 7.51 0.86 0.075 LPN11   1.81804 C1-C6 π* 0.40060 32.32 0.31 0.095 LPO15   1.94078 As14-O17 σ* 0.21155 7.68 0.42 0.053       As14-O19 σ* 0.09141 6.13 0.52 0.051 LPO19   1.85321 C4-As14 σ* 0.13448 13.73 0.44 0.069     1.85321 As14-O17 σ* 0.21155 12.40 0.34 0.059 LPO19   1.82500 As14-O15 σ* 0.20270 22.09 0.34 0.078     1.82500 As14-O19 σ* 0.21155 13.48 0.34 0.061   π* 0.41175 C2-C3 π* 0.30266 230.77 0.01 0.078 C4-As14 σ* 0.13448 As14-O19 σ* 0.09141 41.40 0.01 0.059

Table 5: The second-order perturbation energies E (2) (kcal/mol) corresponding to the most important charge transfer interactions (donor-acceptor) in pAsA by B3LYP/6- 31+G** method.