Explaining Hydrogen Atom's Line Spectra: The Rutherford Atomic Model

[roshan2004]

Why the rutherford atomic model can't explain the line spectra of the hydrogen atom?

 

[malawi_glenn]

the most essential is that a spiralling charge will emit radiation and thus loose energy making the atom collapse.

 

[roshan2004]

But,that only explains the unstability of atom.The question is about the spectra.

 

[malawi_glenn]

if the atom is unstable, will there be a spectra? Well, it will be continuous -> compare with bremsstrahlung spectra.

 

[roshan2004]

So,Can I say this-Because the atom is spiralling down towards the nucleus,it will continuoulsly be giving the radiation forming a single wavelength,continuous spectra.

 

[malawi_glenn]

I would not say that it will forming a single wavelength, that is a discrete spectrum. Your sentence is a self contradiction.

 

[roshan2004]

So,how do I explain the reason then...

 

[malawi_glenn]

you just drop the "forming a single wavelength" part.

 

[roshan2004]

How about this-Rutherford's model suggests that the electrons can float around at any energy level they want, and that photons of any frequency or wavelength can be emitted.

 

[malawi_glenn]

no electrons can not float around as they want! The rutherford model is a classical, non-quantum, model where electrons are orbiting the nuclei as planets orbiting the sun.

But the electrons are then under a radial acceleration, centripetal acceleration, and accelerating charges will emit radiation of continuous spectrum - there will be no stable energy levels and no atom will be stable.

 

[roshan2004]

So it means that they are continuously giving radiation of same type in rutherford which give a continuous radiation.

 

[malawi_glenn]

the radiation is continuous in time and in wavelength

 

[roshan2004]

Thanks mate,are there any links that you know which has got the lectures on bohr's model of atom along with rutherford's and sommerfield's.

 

[malawi_glenn]

http://hyperphysics.phy-astr.gsu.edu/HBASE/bohrcn.html#c1

http://hyperphysics.phy-astr.gsu.edu/HBASE/quacon.html#quacon

http://en.wikipedia.org/wiki/Bohr_model

http://www.phys.au.dk/mastkvant/neclet/NOTE2.pdf

http://www.nobeliefs.com/atom.htm

 

[roshan2004]

Why the orbit energy in bohr model is negative?

 

[malawi_glenn]

all bound states has negative energy. (It all boils down to where you define the 0 level of energy).

 

[roshan2004]

What is meant by bound states?

 

[malawi_glenn]

have you not done classical mechanics with planetary orbits and stuff? :O

roughly speaking, a system is bound if it's kinetic energy in the centre of mass system is smaller than the potential energy.

 

[roshan2004]

Thanks

 

[malawi_glenn]

and since one often counts potential energy as negative, the energy of a bound system will become negative.

 

[roshan2004]

Really appreciate all your labour mate.

 

[Bob_for_short]

Why the Rutherford atomic model can't explain the line spectra of the hydrogen atom?

In a certain approximation, it can. If your electron starts falling from infinity (or just from very distant place), it radiates a quasi-continuous spectrum. This is called a radiative recombination. But it stops falling into the potential well before reaching the nucleus: its "lowest" orbit is determined with quantum mechanics. In fact, the electron can be captured by the nucleus in some cases (http://en.wikipedia.org/wiki/K-capture). In this sense, it can "reach" the nucleus and form a neutral particle with a proton.

Bob.

 

[malawi_glenn]

But electron capture is a quantum mechanical property and has nothing to do with an electron 'spiralling' down towards the nucleus etc.