Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: jeffreyH on 07/12/2017 21:36:17

Title: Is there a centre of charge?
Post by: jeffreyH on 07/12/2017 21:36:17

We have a combined centre of gravity of objects in a gravitationally bound system. Can we also have a combined centre of charge between the electron and proton in a hydrogen atom?

Title: Re: Is there a centre of charge?
Post by: Bored chemist on 07/12/2017 21:55:12

Yes, the centre of charge for an isolated hydrogen (or other) atom is, on average at the centre of mass,
 but there can be differences in their locations- it's called polarisation.

Title: Re: Is there a centre of charge?
Post by: chiralSPO on 07/12/2017 22:05:38

Quote from: jeffreyH on 07/12/2017 21:36:17

We have a combined centre of gravity of objects in a gravitationally bound system. Can we also have a combined centre of charge between the electron and proton in a hydrogen atom?

Absolutely. Just following up on the reply from bored chemist.


In a lone atom, the center of mass and center of charge is likely to be the same. But in molecules this is usually NOT the case. Some small and highly symmetric molecules are nonpolar, but mose molecules have an uneven distribution of charge throughout, resulting in a net electric dipole moment. Note that even molecules with no dipole moment, they may well havenonzero  tetrapole, octapole, hexadecapole etc. moments.

Also, because charge comes in two flavors, and as far as we can tell gravity has only one, there are some important differences between electric fields and gravitational fields.