Change search
ReferencesLink to record
Permanent link

Direct link
Using MD snapshots in ab initio and DFT calculations: OH vibrations in the first hydration shell around Li+(aq)
KTH, School of Biotechnology (BIO), Theoretical Chemistry.
2005 (English)In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 109, no 23, 5144-5152 p.Article in journal (Refereed) Published
Abstract [en]

The average OH stretching vibrational frequency for the water molecules in the first hydration shell around a Li+ ion in a dilute aqueous solution was calculated by a hybrid molecular dynamics + quantum-mechanical (MD + QM) approach. Using geometry configurations from a series of snapshots from an MD simulation, the anharmonic, uncoupled OH stretching frequencies were calculated for 100 first-shell OH oscillators at the B3LYP and HF/6-31G(d,p) levels of theory, explicitly including the first shell and the relevant second shell water molecules into charge-embedded supermolecular QM calculations. Infrared intensity-weighting of the density-of-states (DOS) distributions by means of the squared dipole moment derivatives (which vary by a factor of 20 over the OH stretching frequency band at the B3LYP level), changes the downshift from approximately -205 to -275 cm(-1) at the B3LYP level. Explicit inclusion of relevant third-shell water molecules in the supermolecular cluster leads to a further downshift by approximately -30 cm-1. Our final estimated average downshift is approximately -305 cm-1. The experimental value lies somewhere in the range between - 290 and -420 cm-1. Also, the absolute nu(OH) frequency is well reproduced in our calculations. In-liquid instantaneous correlation curves between nu(OH) and various typical H-bond strength parameters such as R((OO)-O-...), R((HO)-O-...), the intramolecular OH bond length, and the IR intensity are presented. Some of these correlations are robust and persist also for the rather distorted instantaneous geometries in the liquid; others are less so.

Place, publisher, year, edition, pages
2005. Vol. 109, no 23, 5144-5152 p.
Keyword [en]
aluminum(iii) chloride solution, molecular-dynamics simulations, liquid water, aqueous-solutions, geometry optimization, infrared-spectroscopy, ionic hydration, hdo molecules, monte-carlo, spectrum
URN: urn:nbn:se:kth:diva-14832ISI: 000229751600023OAI: diva2:332873
QC 20100525Available from: 2010-08-05 Created: 2010-08-05Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Hermansson, Kersti
By organisation
Theoretical Chemistry
In the same journal
Journal of Physical Chemistry A

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 19 hits
ReferencesLink to record
Permanent link

Direct link