Is 1 cm equal to 8.066 meV-1 in unit conversion?

AI Thread Summary
The discussion clarifies the conversion between energy and wavelength units, specifically addressing whether 1 cm equals 8.066 meV-1. It confirms that 1 meV is indeed equivalent to 8.066 cm-1, but emphasizes the importance of unit notation, noting that meV-1 refers to the reciprocal of milli-electronvolts. Participants explain the relationship using the equation E=hf and the conversion factors involved. The conversation highlights the common pitfalls in unit conversions, particularly in condensed matter physics. Understanding these conversions is essential for accurate calculations in related fields.
Rajini
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Dear PF members,
We know that 1 meV = 8.066 cm-1. So now can i say 1 cm = 8.066 meV-1 ?
thanks for your reply.
Ps: 1 cm-1 = 0.124 meV.
 
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I'm not sure what you are saying here Rajini because your units don't balance.An eV is a unit of energy.
 
This is a common "short form" used in condensed matter/solid state physics, especially in optical conductivity measurement. 1 eV is "equivalent" to 8.0655 x 10^3 cm^-1. It's one of those simplified notation that sets k=h=c=1.

Zz.
 
Whoops...sorry Rajini and thank you ZapperZ.Can you please give me some ideas about where to google to get more information?
 
Dadface said:
Whoops...sorry Rajini and thank you ZapperZ.Can you please give me some ideas about where to google to get more information?

It actually is a straight-forward conversion.

Start with E=hf.

So if you have 1 eV = hf, it gives you an equivalence

1 eV == 2.4 e14 Hz

but we know that f = c/lambda.

So 1/lambda = cf = 8.05 e3/cm == 1 eV.

The list of values of the conversion from 1 eV into frequency, 1/cm, and Kelvin can be found in the inside back cover of Ashcroft and Mermin's Solid State Text.

Zz.
 
Hi, how i calculate (and many ppl. do)..
we know
E=hc/\lambda
and so
1/\lambda=E/(hc)
Now by taking E = 1 eV, h in eVs and c in cm/s
one will get 1/\lambda = 8066 cm-1 (for E= 1 eV).
So 1 meV = 8.066 cm-1
But my questions is whether the following is correct or not!?
1 cm = 8.066 meV-1 [i just reversed the units!]

thanks for your reply
 
yes i solved this problem..sorry
 
THank you ZapperZ.There was I thinking it might be something complicated.
 
Rajini said:
But my questions is whether the following is correct or not!?
1 cm = 8.066 meV-1 [i just reversed the units!]

Yes, but remember here that it's (meV)-1 and not milli-(eV)-1,
just as cm-1 is taken to mean 1/centimeters and not 100ths of 1/m.

First time I worked with cm-1 I kept being off by a factor of 10,000 for some reason :)
 
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