Due to wide variety of biological and pharmacological activities of benzimidazole derivatives, the differences between 2-(2-Chlorophenyl)benzimidazole and 2-(4-Chlorophenyl) benzimidazole were researched by employing terahertz time-domain spectroscopy and density functional theory systematically. Although the only difference between their molecular configurations is the arrangement of chlorine atom on chlorophenyl ring, there are distinctive differences in their fingerprint spectra in the range of 0.2–2.5 THz, such as amount, amplitude, and frequency position of absorption peaks. The validity of these results was confirmed by the theoretical results simulated by using density functional theory. The possible reasons of these differences originate from the different van der Waals forces and the different dihedral angles of the molecules within crystal cell. These results indicate the importance of this spectral range as a conformational fingerprint region where even minor changes in the molecular configuration lead to major differences in its THz absorption.

由于苯并咪唑衍生物的多种生物学和药理活性，利用太赫兹时域光谱和密度泛函理论系统研究了2-（2-氯苯基）苯并咪唑和2-（4-氯苯基）苯并咪唑之间的差异。尽管它们的分子构型之间唯一的区别是氯原子在氯苯环上的排列，但它们的指纹图谱在0.2–2.5 THz的范围内存在明显的差异，例如吸收峰的数量，幅度和频率位置。通过使用密度泛函理论模拟的理论结果证实了这些结果的有效性。这些差异的可能原因源自晶体细胞内分子的范德华力不同和分子的二面角不同。这些结果表明该光谱范围作为构象指纹区域的重要性，在该构象指纹区域中，即使分子构型的微小变化也会导致其THz吸收发生重大差异。