TY - JOUR
T1 - Structured water around ions - FTIR difference spectroscopy and quantum-mechanical calculations
AU - Fischer, Wolfgang B.
AU - Fedorowicz, Adam
AU - Koll, Aleksander
PY - 2001
Y1 - 2001
N2 - Saturated solutions of LiCl, NaCl, KCl, NH4Cl, NH4Br, NH4I, CaCl2 and MgCl2 against pure water are recorded using attenuated total reflection FTIR difference spectroscopy. All ions show distinct effects on the water bands which result in several positive and negative bands. For the anions, band shifts to higher frequencies are found in the sequence F-, Cl-, Br-, I-. An opposite shift is observed for the cations in the sequence NH4+, K+, Na+, Li+. With the shift of the band envelope to lower wavenumbers, bands are visible which are due to the effect of Fermi resonance (v1 + 2v2). Quantum-mechanical calculations using the GAUSSIAN 94 program package with the 6311G+ +(3df,3pd) basis set were performed for the ions and one water molecule. Bands were calculated for water-ion formations in C2v and Cs symmetry. The observed and calculated frequency shifts correspond to changes in the geometry and charge separation of the water molecules opposing the ion.
AB - Saturated solutions of LiCl, NaCl, KCl, NH4Cl, NH4Br, NH4I, CaCl2 and MgCl2 against pure water are recorded using attenuated total reflection FTIR difference spectroscopy. All ions show distinct effects on the water bands which result in several positive and negative bands. For the anions, band shifts to higher frequencies are found in the sequence F-, Cl-, Br-, I-. An opposite shift is observed for the cations in the sequence NH4+, K+, Na+, Li+. With the shift of the band envelope to lower wavenumbers, bands are visible which are due to the effect of Fermi resonance (v1 + 2v2). Quantum-mechanical calculations using the GAUSSIAN 94 program package with the 6311G+ +(3df,3pd) basis set were performed for the ions and one water molecule. Bands were calculated for water-ion formations in C2v and Cs symmetry. The observed and calculated frequency shifts correspond to changes in the geometry and charge separation of the water molecules opposing the ion.
UR - http://www.scopus.com/inward/record.url?scp=0035723019&partnerID=8YFLogxK
U2 - 10.1039/b103551g
DO - 10.1039/b103551g
M3 - Article
AN - SCOPUS:0035723019
SN - 1463-9076
VL - 3
SP - 4228
EP - 4234
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 19
ER -