Term
| Ultraviolet-Visible Spectroscopy |
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Definition
| A type of optical spectroscopy that measures the absorption of light in the visible and ultraviolet regions of the spectrum; UV-Vis spectra primarily provide structural information about the conjugation of multiple bonds in the compound being analyzed. Also called UV-Vis Spectroscopy. |
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Term
| Electromagnetic radiation |
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Definition
| Various forms of electromagnetic waves that propagate at the speed of light; includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays |
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Term
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Definition
| The full range of electromagnetic frequencies from radio waves to gamma rays. |
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Definition
| A plot of the wavelength of a region of the spectrum versus the absorbance at each wavelength |
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Definition
| The wavelength at which the absorption is at a maximum. Also called absorbance peak |
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Term
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Definition
| A physical law stating that the quantity of light absorbed by a substance dissolved in a nonabsorbing solvent is directly proportional to the concentration of the substance and the path length of the light through the solution, according to the equation: A = ε ∙ c ∙ l, where A is the absorbance at a particular wavelength, ε is the extinction coefficient, c is the concentration, and l is the path length in cm of the light beam through the sample cell. Also called Beer's Law |
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Term
| Extinction coefficient, ε |
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Definition
| The proportionality constant that relates the concentration of a compound to its absorbance of light, as defined by the Beer-Lambert Law: ε = A / ( c ∙ l ), where A is the absorbance at a particular wavelength, c is the concentration, and l is the path length in cm of the light beam through the sample cell. Also called molar absorptivity when units are M-1 cm-1 . |
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Term
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Definition
| The distance between consecutive peaks (or troughs) of a wave; often expressed in μm; the product of the wavelength and the frequency is the speed of light: c = λ ∙ υ. |
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Term
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Definition
| The number of complete wave cycles that pass a fixed point in a second; or the number of reversals of the electromagnetic field per second; usually expressed in Hertz (Hz), which is cycles per second (cps or s-1 ). |
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Definition
| A measure of the frequency of a wave in cycles per second (cps or s-1 ). |
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Definition
| Excitation of a π electron in a HOMO bonding π orbital to a LUMO antibonding π* orbital by ultraviolet or visible light. |
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Term
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Definition
| Excitation of an electron in a lone-pair nonbonding n orbital to a LUMO antibonding π* orbital by ultraviolet or visible light. |
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