Research on the differences between 2-(2-Chlorophenyl)benzimidazole and 2-(4-Chlorophenyl)benzimidazole based on terahertz time domain spectroscopy

Due to different arrangement of chlorine atom on chlorophenyl ring, there are different crystal structure with different van der Waals forces and different dihedral angles of the molecules within crystal cell for 2-(2-Chlorophenyl)benzimidazole and 2-(4-Chlorophenyl) benzimidazole. These characteristics were clearly demonstrated by employing terahertz time-domain spectroscopy with their fingerprint spectra in the range of 0.2-2.5 THz. The validity of these results is confirmed by the theoretical results simulated using density functional theory.188