RESULTS AND DISCUSSION
Forty-one density functionals shown in Table 2 has been tested, including eight GGA, three meta-GGA, and thirty hybrid functionals. Among them, additional D2, D3, and D3BJ dispersion corrections were also considered for five (B97D functional employing D2 correction as a default in the program), thirteen, and eight functionals (Table 2), respectively. Therefore, the total 67 methods have been applied.