# Need some help with wave function/QM properties. Thanks!

1. Nov 7, 2012

### nukeman

Can someone explain the following statement for me? The best you can, would really appreciate it.

"A wave function or wavefunction is a probability amplitude in quantum mechanics describing the quantum state of a particle and how it behaves. "

I am trying to learn/understand how something like a molecule vibrates, and how this vibration creates a wave function that can affect other particles, or other things.

2. Nov 7, 2012

### Matterwave

A wavefunction psi(x,t) is some complex function of space and time. If you take the absolute square of it |ps(x,t)|^2 then you get roughly the probability distribution that the particle is in position between x and x+dx, at time t.

Last edited: Nov 7, 2012
3. Nov 14, 2012

### nukeman

In the simpliest terms possible, can you expand the following statement?

"A wave function or wavefunction is a probability amplitude in quantum mechanics describing the quantum state of a particle and how it behaves."

4. Nov 14, 2012

### DrewD

That will prove difficult since a wave from a vibrating molecule has nothing to do with the wavefunction. It may create compression waves in a material, but that is completely different.

Do you know what a probability distribution is? In QM there is a function that is a complex function (as in $i$) called a wavefunction. If you want to know the probability that a particle will be found in a certain area, you integrate the absolute square of the wavefunction over the area in question. The absolute square of the wavefunction is the complex conjugate of the function times the function.

The wavefunction is normalized which means that if you integrate over all space it equals 1 (which just means that the particle will be found somewhere if you can look everywhere).

5. Nov 14, 2012

### nukeman

Not too sure on probability distribution. Is it mainly the statistical probability of something like a particle, being some where we are looking at?

So you are saying that Quantum mechanical waves would have nothing to do with a vibrating molecule?

Is there anything quantum mechanical about a vibrating molecule?