What is Molar Absorptivity?

Molar absorptivity, also known as the molar extinction coefficient, is a measure of how strongly a chemical species absorbs light at a given wavelength. It is a fundamental property in spectroscopy and is used in the Beer-Lambert Law to relate the absorption of light to the properties of a material through which the light is traveling. Molar absorptivity is typically expressed in units of L/(mol·cm) and is denoted by the symbol ε (epsilon).

How to Use the Molar Absorptivity Calculator

Step 1: Enter the Absorbance

Input the absorbance value of your sample in the first field. This is a dimensionless quantity typically measured using a spectrophotometer.

Step 2: Input the Concentration

Enter the concentration of your solution in mol/L (moles per liter) in the second field. Make sure to convert your concentration to this unit if it’s in a different format.

Step 3: Specify the Path Length

Input the path length of your sample cuvette in centimeters. The default value is set to 1 cm, which is standard for many spectrophotometric measurements, but you can adjust this if your setup differs.

Step 4: Calculate the Result

Click the “Calculate” button. The calculator will use the Beer-Lambert Law to determine the molar absorptivity based on your inputs.

Step 5: Interpret the Results

The calculated molar absorptivity will be displayed in units of L/(mol·cm). The tool also provides a brief explanation of how the result was calculated using the Beer-Lambert Law.

By following these steps, you can quickly and accurately determine the molar absorptivity of your sample using the Beer-Lambert Law. This tool is invaluable for spectroscopy applications in chemistry, biochemistry, and related fields.