Table 1. Total Energies (in Hartree) and Dipole Moment of the Studied Compounds.

compounds	DFT/B3LYP SCF energy (Hartree)	dipole moment (Debye)	DFT/ωB97XD SCF energy (Hartree)	dipole moment (Debye)	M06-2X SCF energy (Hartree)	dipole moment (Debye)	MP2 SCF energy (Hartree)	dipole moment (Debye)
azepane	–291.242427	1.15	–291.204586	1.24	–291.146194	1.25	–290.588428	1.25
oxepane	–311.110443	1.44	–311.067495	1.55	–311.014223	1.58	–310.44712	1.59
thiepane	–634.099848	1.93	–634.057711	1.99	–633.992997	1.95	–633.05895	1.99
FCHP	–374.464569	2.33	–374.421952	2.37	–374.358411	2.35	–373.70489	2.42
ClCHP	–734.832824	2.74	–734.788052	2.69	–734.717848	2.68	–733.690514	2.73
BrCHP	–2848.769627	2.87	–2848.753278	2.72	–2848.690151	2.82	–2846.67841	2.86
CHP	–275.208609	0.012	–275.175393	0.0049	–275.111237	0.0055	–274.561808	0.0054