Selective Probing of the OH or OD Stretch Vibration in Liquid Water Using Resonant Inelastic Soft-X-Ray Scattering
2013 (English)In: Physical Review Letters, ISSN 0031-9007, Vol. 111, no 19, 193001- p.Article in journal (Refereed) Published
High-resolution O 1s resonant inelastic x-ray scattering spectra of liquid H2O, D2O, and HDO, obtained by excitation near the preedge resonance show, in the elastic line region, well-separated multiple vibrational structures corresponding to the internal OH stretch vibration in the ground state of water. The energy of the first-order vibrational excitation is strongly blueshifted with respect to the main band in the infrared or Raman spectra of water, indicating that water molecules with a highly weakened or broken donating hydrogen bond are correlated with the preedge structure in the x-ray absorption spectrum. The vibrational profile of preedge excited HDO water is well fitted with 50% +/- 20% greater OH-stretch contribution compared to OD, which strongly supports a preference for OH being the weakened or broken H-bond in agreement with the well-known picture that D2O makes stronger H-bonds than H2O. Accompanying path-integral molecular dynamics simulations show that this is particularly the case for strongly asymmetrically H-bonded molecules, i.e., those that are selected by preedge excitation.
Place, publisher, year, edition, pages
2013. Vol. 111, no 19, 193001- p.
IdentifiersURN: urn:nbn:se:su:diva-97653DOI: 10.1103/PhysRevLett.111.193001ISI: 000326887500001OAI: oai:DiVA.org:su-97653DiVA: diva2:680417