Re: Why is the Hydrogen atom spin 1/2?

[top posting fixed]

On 4-Oct-2005, quach.james@xxxxxxxxx
wrote in message <1128475809.047591.15680@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>:

> Jim Heckman wrote:
>
> > On 3-Oct-2005, quach.james@xxxxxxxxx
> > wrote in message
> > <1128336634.336283.241880@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>:
> >
> > > Why is the Hydrogen atom spin 1/2, when it consists of an election
> > > (spin 1/2), proton (spin 1/2) and neutron (spin 1/2)?
> >
> > Two of the three spins add 'opposite' to each other and cancel out,
> > so only one of the spin-1/2's is left over.
>
> What about for the Hydrogen atom when there exists only a proton and
> electron?

Then the total spin is either 0 or 1, depending on whether the
proton and electron spins are aligned together or opposite each
other. (This is a simplified picture; quantum mechanics makes it
more complicated than just adding the spins together.) The two spin
states have different energy levels, and atoms transitioning
between them give rise to the famous 21-cm hyperfine spectral line.

--
Jim Heckman
.

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