Reflectivity of metals and elements

[mdergance3]

Hello all,
I was wondering if there was a way to calculate the reflectivity of differing wavelengths of light hitting an element based upon its physical properties. I know that it is based on how the atoms of the material are excited based upon the wavelength hitting it. I eventually want to determine what wavelengths will reflect off of a specific metal in a pile of other stuff in order to locate said metal.
Any help will be appreciated,
Thank you

 

[granpa]

if the atom were excited then the light would be absorbed.

 

[ZapperZ]

Hello all,
I was wondering if there was a way to calculate the reflectivity of differing wavelengths of light hitting an element based upon its physical properties. I know that it is based on how the atoms of the material are excited based upon the wavelength hitting it. I eventually want to determine what wavelengths will reflect off of a specific metal in a pile of other stuff in order to locate said metal.
Any help will be appreciated,
Thank you

Metals and atoms are two entirely different beasts. In fact, solids and atoms are two entirely different beasts. If they are the same, then atomic-molecular physics would be identical to Solid State Physics, and having two separate field of studies would be redundant.

Zz.

 

[mdergance3]

So does that mean there isn't a way to calculate what wavelengths of light will reflect off of a metal and that it can only be done experimentally?

 

[granpa]

look up a formula for the conductivity of a metal as a function of frequency
or 'frequency dependent conductivity' or 'AC conductivity'.
http://en.wikipedia.org/wiki/Mathematical_descriptions_of_opacity
https://www.physicsforums.com/archive/index.php/t-217573.html

 

[f95toli]

So does that mean there isn't a way to calculate what wavelengths of light will reflect off of a metal and that it can only be done experimentally?

It can be calculated by "anyone" for an idealized metal (which is what Granpa is linking to). However, for real metals you need some pretty sophisticated computer models to even get started.
It also depends on what you mean by "light"; visible light covers only a small part of the spectrum; much of the interesting stuff goes on at other wavelengths (e.g. in the IR part of the spectrum).
What you describe is a form of spectroscopy, and my guess is that the visible part of the spectrum is not the best choice for differentiating between different metals.

 

[Redbelly98]

Hello all,
I was wondering if there was a way to calculate the reflectivity of differing wavelengths of light hitting an element based upon its physical properties. I know that it is based on how the atoms of the material are excited based upon the wavelength hitting it. I eventually want to determine what wavelengths will reflect off of a specific metal in a pile of other stuff in order to locate said metal.
Any help will be appreciated,
Thank you

Would you want to identify just elemental metals, or all metals including the many varieties of alloys used to manufacture goods?

Also, reflectivity of a metal can change over time as an oxide layer slowly forms on its surface. Reflectivity will also depend on the degree of surface smoothness/roughness.

There are many variable factors to consider here.