Bouger-Lambert law

The Bouger-Lambert-Beer Law is fulfilled with limitations in molecular absorption spectrophotometry (Skoog et al., 2008). 

This equation has been alternately referred to as the Beer-Lambert law, the Bouger-Beer law, or more simpty. Beefs law. This combined law states that the amount of light absorbed (absorbance or extinction) is proportional to the concentration of the absorbing substance and to the thickness of the absorbing material (path-length). The quantity I /l is known as the absorbance or the optical density (O.D.). The reverse, I/l is known as the transmittance, T (the amount of light which escapes absorption and is transmitted). 

One necessary input for ealeulating the heat source term is the laser intensity Ix=o that reaehes the joining plane. This is determined experimentally as deseribed above for the motionless laser beam (Vscan= Om/s). Over the y-axis and in the direction in which the laser beam moves (z-direction), this corresponds to a Gaussian intensity distribution. Assuming that the Lambert-Bouger law is vahd, the thermal source term works out at (Eqn. 2) ... 

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