Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland.
J Phys Chem A. 2010 Mar 18;114(10):3495-502. doi: 10.1021/jp911515f.
Six trans-trans and five trans-cis dimeric structures of formic acid (HCOOH) are revealed by ab initio calculations. Four trans-trans and two trans-cis dimers are identified in the IR absorption spectra in argon matrices. The trans-cis dimers are obtained by narrow-band IR excitation of the vibrational transitions of the trans-trans dimers. Two trans-trans (tt3 and tt6) and one trans-cis (tc4) dimer are characterized experimentally for the first time. The tunneling decay rates of two trans-cis dimers (tc1 and tc4) are evaluated at different temperatures. A greater lifetime of the trans-cis dimers at elevated temperatures compared to the cis-monomer suggests that the high-energy conformers can be stabilized upon hydrogen bonding.
通过从头计算揭示了甲酸（HCOOH）的六种反式反式和五种反式顺式二聚体结构。在氩基质的红外吸收光谱中鉴定出了四种反式反式和两种反式顺式二聚体。通过窄带红外激发反式反式二聚体的振动跃迁获得了反式顺式二聚体。首次实验表征了两个反式反式（tt3 和 tt6）和一个反式顺式（tc4）二聚体。在不同温度下评估了两个反式顺式二聚体（tc1 和 tc4）的隧道衰变速率。与顺式单体相比，高温下反式顺式二聚体的寿命更长，这表明高能构象可以通过氢键稳定。
