Download presentation

Presentation is loading. Please wait.

Published byHamza Gowell Modified over 3 years ago

1
The interactions of light with matter Ignoring fluorescence, the interactions of light with matter can be expressed thus: I o = I reflected + I scattered + I absorbed + I transmitted transparent material translucent material

2
The Beer-Bouger-Lambert Law and max The Beer’s law: At a given the proportion of light absorbed by a transparent medium is independent of the intensity of the incident light and is proportional to the number of absorbing molecules through which the light passes. I 0 is the intensity of incident light I is the intensity of transmitted light k is the absorption coefficient l is the path length through the sample is molar extinction coefficient or molar absorptivity c is the concentration in mol/L So k ≈ 2.303 c

3
Absorption Intensity and Oscillator Strengths The shape of an electronic absorption is due primarily to the vibrational sublevels of the electronic states (Franck-Condon Principle). The intensity of an absorption band is often and conveniently described in terms of the maximum of molar absorptivity max but, unfortunately, this value is not directly related to any quantity obtained directly from theory. A more related value is the dipole strength D and represents the electronic transition probability. Δ is the bandwidth at max /2 In an electronic transition, an electron is promoted from one molecular orbital to a higher-lying molecular orbital while the molecule goes from its ground state (S=0) to its excited states (S=1, 2,3,…). This migration of charge creates a momentary dipole, called the electric transition dipole moment ( ), which has both direction and intensity (vector). ן ן = √D

4
Electronic, Vibrational, and Rotational States of Molecules S = 0

5
The Franck-Condon Principle

6
Classification of Electronic Transitions in Molecules

Similar presentations

OK

Microplate reader spectrophotometer. The Beer-Lambert Law A=abc Now let us look at the Beer-Lambert law and explore it's significance. A is absorbance.

Microplate reader spectrophotometer. The Beer-Lambert Law A=abc Now let us look at the Beer-Lambert law and explore it's significance. A is absorbance.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on international business law Ppt on current economic issues in india Ppt on cobb douglas production function Ppt on conservation of species Ppt on power grid india Ppt on human resources development Download ppt on abdul kalam Free download ppt on steve jobs Ppt on cse related topics on personality Ppt on structure in c programming