Formic acid in deuterium and hydrogen matrices |
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| Authors: | Susy Lopes Leonid Khriachtchev |
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| Institution: | 1. CQC, Department of Chemistry, University of Coimbra Coimbra, Portugalsusylopes@qui.uc.pt;3. Department of Chemistry, University of Helsinki Helsinki, Finland |
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| Abstract: | ABSTRACTFormic acid (HCOOH, FA) was studied experimentally, by infrared spectroscopy, in H2 and D2 matrices, with focus on the preparation and characterisation in these matrix media of structures containing the higher-energy (cis) conformer. The cis-FA monomer and the cis-FA?…?N2 complex were successfully produced by selective vibrational excitation of corresponding trans-FA based species, and vibrationally characterised. The tunneling-induced conversion of the cis-FA?…?N2 complex in the studied matrices into the corresponding trans-FA complex was also investigated, and the found tunnelling properties discussed, in particular in comparison with those observed for the spontaneous conversion of cis-FA monomer into trans-FA. This article constitutes the first report on the infrared spectrum of FA conformers and stability of cis-FA monomer in a D2 matrix, and on the structure, spectroscopy and stability of the cis-FA?…?N2 complex in both H2 and D2 matrices. Different attempts to prepare the cis-FA?…?H2O complex in the two investigated matrices are also described in detail, both from previously in situ generated cis-FA monomer followed by thermal mobilisation and by direct selective vibrational excitation of the trans-FA-H2O complex. |
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| Keywords: | Formic acid conformational change matrix isolation infrared-induced conformational isomerisation hydrogen atom tunnelling |
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