Why are metals different colours? I suppose this is because each metal reflects/absorbs differing proportions of certain wavelengths of light, but why do different metals reflect different wavelengths? And why do metals absorb light at all? This is how I understand the reflection of light. It’s all guesswork, so correct me if I’m wrong. A photon hits an electron. The electron absorbs the photon, and is briefly excited to a higher energy state. Generally, this state is unstable and so a photon of equal energy to the one absorbed is reemitted at twice the angle of incidence, reducing the electron to it’s original energy state. It occurs to me that if an electron was excited enough to jump to a stable shell, a photon would not be emitted. Perhaps this is what accounts for the absorption of light. If this model is correct, however, it raises a number of questions. Why does graphite, which has layers of free electrons between each ‘sheet’ of graphite, absorb all light and reflect none? On a somewhat unrelated note, what, on an atomic level, determines the index of refraction of a substance? Does the index of refraction have only to do with the arrangement of atoms/free electrons upon the surface, or does the internal structure influence it? For instance, take diamond. Due to the nature of it’s structure, each diamond atom on the surface has one free bond, while no free electrons exist internally. I suppose the free electrons are what account for the reflection of light on the surface, but can this account for internal reflection? Hmm. That post was a bit of a jumble, so make of it what you will.
-Oli
Sorry, but could you break it down into smaller paragraphs?
Sure. OP with paragraphs coming up. Hopefully, more readable.
Why are metals different colours? I suppose this is because each metal reflects/absorbs differing proportions of certain wavelengths of light, but why do different metals reflect different wavelengths? And why do metals absorb light at all?
This is how I understand the reflection of light. It’s all guesswork, so correct me if I’m wrong. A photon hits an electron. The electron absorbs the photon, and is briefly excited to a higher energy state.
Generally, this state is unstable and so a photon of equal energy to the one absorbed is reemitted at twice the angle of incidence, reducing the electron to it’s original energy state. It occurs to me that if an electron was excited enough to jump to a stable shell, a photon would not be emitted.
Perhaps this is what accounts for the absorption of light. If this model is correct, however, it raises a number of questions.
Why does graphite, which has layers of free electrons between each ‘sheet’ of graphite, absorb all light and reflect none?
On a somewhat unrelated note, what, on an atomic level, determines the index of refraction of a substance?
Does the index of refraction have only to do with the arrangement of atoms/free electrons upon the surface, or does the internal structure influence it?
For instance, take diamond. Due to the nature of it’s structure, each diamond atom on the surface has one free bond, while no free electrons exist internally.
I suppose the free electrons are what account for the reflection of light on the surface, but can this account for internal reflection?
-Oli