# How to convert cm^-1 into erg or joules

1. Feb 5, 2010

### AutisticAlien

I'm not sure if this is the right place for this, but I can't seem to find how to convert cm^-1 into erg or joules... It's a pretty dumb question, but I can't find the answer anywhere.

2. Feb 5, 2010

### uart

Re: Energy?

You cant, because cm^(-1) is not a unit of energy. The base units of energy are m l t^(-2). For example Ergs are grams cm seconds^(-2) and Joules are kg m seconds^(-2).

3. Feb 5, 2010

### uart

Re: Energy?

The only meaning that I can think of for that is perhaps comparing the energy to that of a photon of wavelength one cm.

For example, a photon of wavelength 1mm would have an energy of 10 cm^(-1) and so on.

In that case the conversion factor would just be the energy of a photon wavelength 1cm, which is 100 h c, or about 1.99 x 10^(-23) Joules.

In what context did you see this unit used Alien?

4. Feb 5, 2010

### AutisticAlien

Re: Energy?

Failed to mention context, sorry. But yes, it was the way you predicted. Thank you very much!

It was a Chemistry problem about crystal fields.