6533b7d6fe1ef96bd1265ca3

RESEARCH PRODUCT

Conformation resolved induced infrared activity: trans- and cis-formic acid isolated in solid molecular hydrogen

David T. AndersonMia MelavuoriKseniya MarushkevichLeonid KhriachtchevJan LundellLeif O. Paulson

subject

FormatesHydrogenInfrared RaysInfraredFormic acidOvertoneMolecular ConformationAnalytical chemistryAb initiochemistry.chemical_element010402 general chemistrySpin isomers of hydrogen01 natural scienceschemistry.chemical_compound0103 physical sciencesPhysical and Theoretical ChemistryConformational isomerismta116010304 chemical physicsStereoisomerism0104 chemical scienceschemistryQuantum TheoryPhysical chemistryIsomerizationHydrogen

description

We report combined experimental and theoretical studies of infrared absorptions induced in solid molecular hydrogen by different conformers of formic acid (HCOOH, FA). FTIR spectra recorded in the H(2) fundamental region (4120-4160 cm(-1)) reveal a number of relatively strong trans-FA induced Q-branch absorptions that are assigned by studying both FA-doped parahydrogen (pH(2)) and normal hydrogen (nH(2)) samples. The induced H(2) absorptions are also studied for HCOOD doped nH(2) crystals for both the trans and cis conformers that show resolvable differences. Samples containing90% of the higher energy cis-HCOOD conformer are produced by in situ IR pumping of the OD stretching overtone of trans-HCOOD using narrow-band IR light. Minimum energy structures for 1:1 complexes of H(2) and FA are determined using ab initio methods. The measured differences in the cis- versus trans-HCOOD induced spectra are in qualitative agreement with the frequencies and intensities calculated for the identified cluster structures as discussed in terms of the model of specific interactions.

yearjournalcountryeditionlanguage
2011-10-21The Journal of Physical Chemistry A
10.1021/jp204600vhttps://doi.org/10.1021/jp204600v