Question

What is meant by spectroscopy in modern physics? Give an example of an experimental result

Answer 1

Spectroscopy is the process of exposing a substance to some form of radiation, or gathering radiation emitted by the object, and then analyzing that radiation to gather information about the properties of the substance. Different kinds of radiation provide different kinds of information and are used to analyze different kinds of substances.

Ultraviolet-Visible (UV-Vis) Spectroscop-

UV-Vis can be used to obtain a spectrum of colored compounds. In Figure 1A, the absorbance spectrum of a blue dye is shown. The background shows the colors of light in the visible spectrum. The blue dye has a λmaxabsorbance in the orange/red. Figure 1Bshows a spectrum of a red dye, with λmax in the green.

Kinetics can be measured from a plot of absorbance at one wavelength over time. Figure 2 shows a plot of the absorbance of a blue dye (at 630 nm) as it reacts with bleach.

Figure 1. UV-Vis absorbance spectra. A.Blue dye #1 has maximum absorbance in the orange/red. B. Red dye #40 has maximum absorbance in the green.

Figure 2. UV-Vis for kinetics.Absorbance of blue dye #1 as it reacts with bleach. The curve can be fit with an exponential decay, indicating first order kinetics. Please click here to view a