Search results
Results From The WOW.Com Content Network
The SI unit of molar absorption coefficient is the square metre per mole (m 2 /mol), but in practice, quantities are usually expressed in terms of M −1 ⋅cm −1 or L⋅mol −1 ⋅cm −1 (the latter two units are both equal to 0.1 m 2 /mol).
absorption coefficient is essentially (but not quite always) synonymous with attenuation coefficient; see attenuation coefficient for details; molar absorption coefficient or molar extinction coefficient , also called molar absorptivity , is the attenuation coefficient divided by molarity (and usually multiplied by ln(10), i.e., decadic); see ...
Variable pathlength absorption spectroscopy uses a determined slope to calculate concentration. As stated above this is a product of the molar absorptivity and the concentration. Since the actual absorbance value is taken at many data points at equal intervals, background subtraction is generally unnecessary.
Some physical constraints are usually incorporated in the calculations. For example, all the concentrations of free reactants and species must have positive values and association constants must have positive values. With spectrophotometric data the calculated molar absorptivity (or emissivity) values should all be positive.
3. When |sortable= is used, no unit is added by the template (expected: put in top of table column). 4. When value is calculated, unit g/mol is added by template. 5. There is automatic no conversion from g to kg.
In science, absorptivity may refer to: Molar absorptivity, in chemistry, a measurement of how strongly a chemical species absorbs light at a given wavelength; Absorptance, in physics, the fraction of radiation absorbed at a given wavelength; Emissivity § Absorptivity, information on the radiometrical aspect
When an isosbestic plot is constructed by the superposition of the absorption spectra of two species (whether by using molar absorptivity for the representation, or by using absorbance and keeping the same molar concentration for both species), the isosbestic point corresponds to a wavelength at which these spectra cross each other.
In this example, the reflectance spectrum of the poly-silicon was measured on a blanket area containing the poly-silicon, from which its n and k spectra were determined in accordance with the methodology described in this article that uses the Forouhi–Bloomer dispersion equations. Fixed tables of n and k values were used for the SiO 2 and Si ...