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

The differences between 2-(2′-pyridyl)benzimidazole and 2-(4′-pyridyl)benzimidazole are researched by terahertz time-domain spectroscopy and density functional theory systematically. Although the only difference between their molecular configurations is the different arrangement of nitrogen on pyridine ring, 2PBI and 4PBI have large differences in their experimental absorption spectra in the range of 0.2-2.5 THz, such as the amount, amplitude and frequency position of absorption peaks. The validity of these results is confirmed by the theoretical results simulated using density functional theory.156