Formic acid dimers in a nitrogen matrix


Lopes S., Fausto R., Khriachtchev L.

JOURNAL OF CHEMICAL PHYSICS, cilt.148, sa.3, 2018 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 148 Sayı: 3
  • Basım Tarihi: 2018
  • Doi Numarası: 10.1063/1.5010417
  • Dergi Adı: JOURNAL OF CHEMICAL PHYSICS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • İstanbul Kültür Üniversitesi Adresli: Evet

Özet

Formic acid (HCOOH) dimers are studied by infrared spectroscopy in a nitrogen matrix and by ab initio calculations. We benefit from the use of a nitrogen matrix where the lifetime of the higherenergy (cis) conformer is very long (similar to 11 h vs. 7 min in an argon matrix). As a result, in a nitrogen matrix, a large proportion of the cis conformer can be produced by vibrational excitation of the lower-energy (trans) conformer. Three trans-trans, four trans-cis, and three cis-cis dimers are found in the experiments. The spectroscopic information on most of these dimers is enriched compared to the previous studies in an argon matrix. The cis-cis dimers of ordinary formic acid (without deuteration) are reported here for the first time. Several conformational processes are obtained using selective excitation by infrared light, some of them also for the first time. In particular, we report on the formation of cis-cis dimers upon vibrational excitation of trans-cis dimers. Tunneling decays of several dimers have been detected in the dark. The tunneling decay of cis-cis dimers of formic acid as well as the stabilization of cis units in cis-cis dimers is also observed for the first time. Published by AIP Publishing.