Light Absorption Of Solutions Research Articles

Giant absorption of light by molecular vibrations on a chip.

Vibrational overtone spectroscopy of molecules is a powerful tool for drawing information on molecular structure and dynamics. It relies on absorption of near infrared radiation (NIR) by molecular vibrations. Here we show the experimental evidence of giant enhancement of the absorption of light in solutions of organic molecules due to the switch from ballistic to diffusive propagation of light through a channel silicate glass waveguide. We also experimentally address a dynamics of absorption as a function of time of adsorption of the organic molecules on a waveguide. The observed enhancement in diffusion regime is by a factor of 300 in N-Methylaniline and by factor of 80 in Aniline compared to the expected values in the case of ballistic propagation of light in a waveguide. Our results underscore the importance of a guide surface modification and the disordered molecular nano-layer in enhancement of absorption by amines on engineered integrated system.

Investigation of non-linear absorption of light in solutions of cryptocyanine

Non-linear absorption of light in solutions of cryptocyanine in glycerol and methanol at light intensities between 2 × 10 5W/cm 2 and 5 × 10 9W/cm 2 was investigated theoretically and experimentally. Absorption cross sections and lifetimes of the excited states involved in the non-linear absorption process are estimated. Experimental evidence for the stationarity of the process in case of giant laser pulse excitation is given.

Photosensitivity of Iron Chelates

DURING work with iron chelates, it was noted that many chemical analyses for total iron were inconsistent when repeated at intervals on solutions left standing on the laboratory bench in the light. A sensitive method was then devised for the estimation of the chelated iron molecule as a whole, based on the light-absorption of solutions in the ultra-violet region. Dilute solutions (approximately 0.0001 M) of the di-sodium iron ethylenediaminetetracetate have an absorption curve with a maximum at about 260 mµ. This peak is well separated from, and is much more pronounced than, that of the di-sodium ethylenediaminetetracetate itself at about 210 mµ. Therefore, the optical density at 260 mµ. as determined by a spectrophotometer, was used as a measure of the chelated iron present in solutions of the di-sodium iron compound.

The absorption of light in solutions of the rare earth salts

For completion the series of previous publications on rare earths spectra the absorption spectra of aqueous solutions of europium, terbium and erbium salts are reported. A list of the oscillator strengths of all rare earths is given and the results are shown in a diagram.