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Molar Extinction Coefficient Equation:
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The molar extinction coefficient (ε) is a measure of how strongly a chemical species absorbs light at a particular wavelength. It is a fundamental parameter in spectroscopy that quantifies the absorption characteristics of a substance.
The calculator uses the Beer-Lambert Law equation:
Where:
Explanation: The equation relates the absorbance of a solution to the concentration of the absorbing species and the path length through which light travels.
Details: The molar extinction coefficient is crucial for quantitative analysis in spectroscopy, determining concentrations of unknown samples, and characterizing the optical properties of molecules.
Tips: Enter absorbance (unitless), concentration in molarity (M), and path length in centimeters (cm). All values must be valid and greater than zero.
Q1: What is the typical range for molar extinction coefficients?
A: Molar extinction coefficients typically range from 10 to 10⁵ M⁻¹·cm⁻¹, with values above 10,000 considered strong absorbers.
Q2: Does the extinction coefficient depend on wavelength?
A: Yes, the molar extinction coefficient is wavelength-dependent and is usually specified at the wavelength of maximum absorption.
Q3: What factors affect the molar extinction coefficient?
A: The coefficient depends on the molecular structure, solvent, temperature, and pH of the solution.
Q4: How is this different from absorption coefficient?
A: The molar extinction coefficient is specific to concentration in moles per liter, while absorption coefficient may refer to other concentration units.
Q5: Can this calculator be used for any wavelength?
A: Yes, but the calculated ε value is specific to the wavelength at which the absorbance measurement was taken.