UV-Vis Absorbance Spectroscopy

A spectrophotometer is a device to measure absorbance of light; an absorption spectrum displays the measured absorbance as a function of wavelength for the compound of interest. Polychromatic (white) light is passed through a monochromator, which selects a narrow band of wavelengths from the incident beam. This light then travels through a sample of pathlength, b, and the radiant power of the emergent, or transmitted, light is measured by the detector. The transmittance of the solution is the fraction of incident radiation transmitted by the solution; the absorbance, the negative log of the transmittance.

This program simulates a UV-Vis spectrophotometer. Absorption spectra for aqueous ions of several transition metals are displayed for a specific ion concentration.

INSTRUCTIONS

1. Select an ion by clicking on one of the five ion option buttons.
2. Set the concentration of the ion solution by adjusting the concentration scroll bar from 0 M to 0.200 M.
3. To view the absorption spectrum, click on the Get Spectrum button.
4. Moving the mouse over the spectrum plot displays wavelength and absorption values at the mouse position. To obtain a peak absorbance, point the mouse to the top of the absorbance curve.
5. More than one spectrum may be viewed at a time. To clear the plot area, click on the clear plot button.