# Why glass is transparent

1. Sep 18, 2009

### hagopbul

hello

my question is why glass is transparent why the photon are traveling in it with out being absorb

use equation & explanation ,

please this Q? for high level Physicist not for any one so pleas if you cant use proper equations DONT REPLY

and why its path are so specific and strait ?

2. Sep 19, 2009

### alxm

Re: photon

Well, a "high level physicist" should already know that there is no single equation that will directly explain the absorbance spectrum of glass or any other material, that such spectra can't be calculated analytically to begin with, and that explaining how to calculate an absorbance spectrum from first principles would require at least a book's worth of text.

I don't think anyone's going to write a textbook for you, so I'd suggest that you either accept a simplified, non-rigorous answer or don't ask.

3. Sep 19, 2009

### hagopbul

Re: photon

{Well, a "high level physicist" should already know that there is no single equation that will directly explain the absorbance spectrum of glass or any other material, that such spectra can't be calculated analytically to begin with, and that explaining how to calculate an absorbance spectrum from first principles would require at least a book's worth of text.

I don't think anyone's going to write a textbook for you, so I'd suggest that you either accept a simplified, non-rigorous answer or don't ask. }

ok i said equations not equation , then you can simplify it i didnt say write it all

4. Sep 20, 2009

### hagopbul

Re: photon

and it is easy to say that i dont know write ?

5. Sep 20, 2009

### alxm

Re: photon

Fine, here's your equation:
$$\hat{H}\Psi = E\Psi$$

Solve the electronic Schrödinger equation for the molecular Hamiltonian of whatever your type of glass is, with whatever its atomic coordinates are, using a unit cell and periodic boundary conditions because it's a solid.

After spending a day or two of supercomputer time figuring that out, note that the band gap is larger than the visual range, and that the thing therefore does not absorb visual light to any significant degree because there's no atomic/molecular transitions that correspond to that particular energy range.

6. Sep 21, 2009

### hagopbul

Re: photon

thank you this is what i was talking about ....any one else [i know that eq, every one knows it]

7. Sep 25, 2009

### hagopbul

Re: photon

no answer ??????

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