Light propagation in air without hitting molecules ?

[toan]

hi,

Could anyone help me the following question?

I am reading light transmission through a slab of air (at the ambient atmosphere). My question is: How much light is transmitted without hitting any air molecules?

In details: An incident light beam propagates through a slab, of some thickness, of air. The output light at the end of the slab can be divided into two parts. The first part is the portion of the incident beam that crosses the air slab without hitting any air molecules. The second part is wavelets that is re-radiated by air molecules (due to scattering and absorption/emission). I am concerned with the first part.


Please help me any specific quantity, links to relevant documents, or hints to calculation,... that you know. Thank very much.

 

[BigJDubs]

The amount of light transmitted without hitting any air molecules will depend on the wavelength of the incident light beam, the thickness of the slab, and the index of refraction of the air. Generally speaking, the longer the wavelength of the light beam and the thicker the slab, the more light will be transmitted without hitting any air molecules. However, even under ideal conditions, some of the light will still be scattered by air molecules. You can use the Beer-Lambert law to calculate the amount of light that is transmitted without hitting any air molecules, as well as the amount of light that is scattered by air molecules.