Internal electric fields in small water clusters [(H2O)n; n = 2-6].
The electric field experienced by a water molecule within a water cluster depends on its position relative to the rest of the water molecules. The stabilization energies and the red-shifts in the donor O-H stretching vibrations in the water clusters increase with the cluster size concomitant with the increase in the electric field experienced by the donor O-H of a particular water molecule due to the hydrogen bonding network. The red-shifts in O-H stretching frequencies show a spread of about ±100 cm(-1) against the corresponding electric fields. Deviations from linearity were marked in the region of 100-160 MV cm(-1), which can be attributed to the strain in the hydrogen bonding network, especially for structures with DDAA and DDA motifs. The linear Stark effect holds up to 200 MV cm(-1) of internal electric field for the average red-shifts in the O-H stretching frequencies, with a Stark tuning rate of 2.4 cm(-1) (MV cm(-1))(-1), suggesting the validity of the classical model in small water clusters.
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. saumiksen@chem.iitb.ac.in naresh@chem.iitb.ac.in.
Saumik
S
Sen
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. saumiksen@chem.iitb.ac.in naresh@chem.iitb.ac.in.
Manjusha
M
Boda
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. saumiksen@chem.iitb.ac.in naresh@chem.iitb.ac.in.
S
S
Venkat Lata
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India. saumiksen@chem.iitb.ac.in naresh@chem.iitb.ac.in.
G
G
Naresh Patwari