What determines colour?

Question

Yes, we see colour because of surfaces absorbing and reflecting certain wavelengths of light.
What determines the specific colour a particular material, molecule, what have you, would reflect?

p.s. If you know, does it have anything to do with the Hamiltonian eigenvalue problem?

Atomic structure? I guessed that much. What about the atomic structure? Can anyone detail something specific about the structure that determines the colour ?

Answer 1

I thought only politics had this much disinformation ...

Picture a photon, the quantum of an electromagnetic wave, traveling through space. Now it collides with an atom. There are four possibilities.

1. It reaches an atom, and the energy of the photon is exactly the amount needed to raise an electron in its outer shell to a higher energy level. That photon is absorbed, and its energy is now stored as the potential energy of that electron in a higher energy orbit.

2. Same as 1, except that electron almost immediately drops to a lower orbit and emits a photon whose energy is equal, or nearly equal, to the incoming photon.

3. No atom in the neighborhood meets the quantum conditions needed to absorb that photon, so it passes on through undisturbed.

4. Same as 3, but the nature of the material (conductivity etc.) is such that the photon cannot proceed, so it (the electromagnetic wave) is reflected or refracted.

Now consider these cases at each frequency of the entire visual spectrum. This determines whether that material, or set of materials, is transparent, opaque, transmissive, or reflective of light at each wavelength.

Answer 2

The frequency of the light. The only connection I can see is that solving the Schroedinger WE involves forming the hamiltonian total energy for the atom and the difference in energy levels obtained gives the frequency of the emitted/absorbed energy when the atom absorbs or emits a photon (deltaE=h*f). As far as I know apart from H-like atoms only (good) approx solutions have been obtained. Maybe 'Not J' would care to elaborate further-I always get stuck at the Hartree-Fock treatment for the eigenfunctions.

Answer 3

A new method has been presented for the numerical computation of the eigenvalues of real Hamiltonian matrices. The method is strongly backward stable, i.e., it is numerically backward stable and preserves the Hamiltonian structure. It is closely related to the square reduced method of Van Loan, but in contrast to that method which may suffer from a loss of accuracy of order p ", where " is the machine precision, the new method computes the eigenvalues to full possible accuracy.

So no.

Answer 4

what determines the color is the wavelength of electromagnetic wave(s) which we perceive.
Light that we see is either reflected by objects or received directly from their source. When light strike an object most of the time, part of its energy is absorbed and part is reflected. the color of an object is therefore determined by the range of light that it reflects.

Light is an electrognetic wave of energy e=hν from that formula you can see that energy varies with the frequency (v) of the electromagnetic wave which can be also indentified by its wavelegth L=v/c with c being the celerity 299792458ms-1)

Finally what determines the colours you see is also the ability of your eye to capture wavelengths and ability of your brain to process the nervous signal sent via the optic nerve.

colors, brightness are like temperature, they are sensed therefore are subjective

Answer 5

The atomic structure of any given material and how it responds to electromagnetic energy impinging upon it.

Answer 6

I think the structures of the atoms determine it.

Answer 7

wavelength of light entering the eye

Answer 8

Its based on skin colour. I.e. the darker you are the darker nipples you have.

Answer 9

What determins a colour is the colour that that colour is not.

Answer 10

good question!
cant wait to see the answers lol