Microsolvation in V+(H2O)n Clusters Studied with Selected-Ion Infrared Spectroscopy.
J Phys Chem A
; 124(6): 1093-1103, 2020 Feb 13.
Article
in En
| MEDLINE
| ID: mdl-31961153
ABSTRACT
Gas-phase ion-molecule clusters of the form V+(H2O)n (n = 1-30) are produced by laser vaporization in a supersonic expansion. These ions are analyzed and mass-selected with a time-of-flight mass spectrometer and investigated with infrared laser photodissociation spectroscopy. The small clusters (n ≤ 7) are studied with argon tagging, while the larger clusters are studied via the elimination of water molecules. The vibrational spectra for the small clusters include only free O-H stretching vibrations, while larger clusters exhibit redshifted hydrogen bonding vibrations. The spectral patterns reveal that the coordination around V+ ions is completed with four water molecules. A symmetric square-planar structure forms for the n = 4 ion, and this becomes the core ion in larger structures. Clusters up to n = 8 have mostly two-dimensional structures, but hydrogen bonding networks evolve to three-dimensional structures in larger clusters. The free O-H vibration of acceptor-acceptor-donor (AAD)-coordinated surface molecules converges to a frequency near that of bulk water by the cluster size of n = 30. However, the splitting of this vibration for AAD- versus AD-coordinated molecules is still different compared to other singly charged or doubly charged cation-water clusters. This indicates that cation identity and charge-site location in the cluster can produce discernable spectral differences for clusters in this size range.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Phys Chem A
Journal subject:
QUIMICA
Year:
2020
Type:
Article
Affiliation country:
United States