10min:

PARDEEP KUMAR, INDRAJIT BHATTACHARYYA, DEBABRATA GOSWAMI, Department of Chemistry, Indian Institute of Technology, Kanpur, 208016, India.

We show how hydrogen-bonding plays a significant role in the measure of Thermal-Lens signal of binary liquid mixtures. We use a two-color thermal-lens pump-probe Z-scan technique to measure the relative magnitude of thermal-lens signal in our binary liquid mixtures, where 1560 nm is the thermal pump and 780 nm is the probe. All the binary liquid mixture show a deviation from the ideal linear behavior when the composition of the mixture is varied. We explain this deviation in terms of the nature of the solvents (hydrogen bond characteristics and the corresponding polar or non-polar nature) due to which they form stronger or weaker hydrogen-bonding with the absorbing solute (methanol, in our case). Our observations are that positive deviation results when the solvent forms weaker hydrogen-bonds (weak solute-solvent interaction) with the absorbing solute, and negative deviation occurs in case of strongly polar solvents forming stronger intermolecular hydrogen-bonds (strong solute-solvent interaction) with the absorbing solute molecules. These confirm our explanation based on the hydrogen bond characteristics.