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

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SUMMARY

The discussion clarifies the conversion between energy and wavelength units, specifically addressing whether 1 cm equals 8.066 meV-1. It is established that 1 meV equals 8.066 cm-1, confirming that the reverse statement is valid. The conversion is based on the relationship between energy (E), Planck's constant (h), and the speed of light (c), with 1 eV equating to approximately 8066 cm-1. The discussion emphasizes the importance of unit notation and precision in calculations.

PREREQUISITES
  • Understanding of energy units, specifically electronvolts (eV) and millielectronvolts (meV).
  • Familiarity with wavelength units, particularly centimeters (cm) and reciprocal centimeters (cm-1).
  • Knowledge of Planck's constant (h) and its role in energy calculations.
  • Basic principles of wave-particle duality in physics.
NEXT STEPS
  • Research the relationship between energy and wavelength using the equation E=hf.
  • Explore the conversion factors between different energy units, including eV, meV, and their corresponding wavelength units.
  • Study the contents of Ashcroft and Mermin's "Solid State Physics" for detailed conversion tables.
  • Learn about the implications of unit notation in scientific calculations to avoid common errors.
USEFUL FOR

Physicists, students in condensed matter physics, and anyone involved in optical conductivity measurements or energy-wavelength conversions will benefit from this discussion.

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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