Thermal de Broglie volume

[JacobTk]

Hi,

I'm new to the forum and as usual I come with the question!

I am trying to recreate the statistical associating fluid theory (SAFT) model based on the following papers:
1. T. Lafitte et al. "Accurate statistical associating fluid theory for chain molecules formed from Mie segments"
2. V. Papaioannou et al. "Group contribution methodology based on the statistical associating fluid theory for theteronuclear molecules formed from Mie segments"

Both of them use the thermal de Broglie volume to calculate the ideal contribution to Helmholtz energy (first paper in eq. A1, second in eq. 5). And that is my problem, I can't find its definition, nothing beyond the thermal de Broglie wavelength.
I contacted the authors and after few emails exchanged I haven't received any satisfying answer or received no answer in the other case.

I would be grateful for every tip!
Cheers,
Jacob

 

[chicopee]

The internet has a ton of sites on thermal de Broglie wavelength. A text book on modern physics which goes into the physics Einstein and the like will expound on De Broglie wavelength. As far as Helmholtz energy get a book on classical and statistical thermodynamics. I studied these topics in the 60's and have been of very little value in my work since then but I do remember them to a slight degree.

 

[JacobTk]

I agree, but it has nothing on the thermal de Broglie volume. That's what I'm looking for

 

[Latexman]

Does the latest Edition of The Properties of Gases and Liquids have anything on it?

Have you taken a deep dive into Aspen? They use SAFT.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[chicopee]

Try this site "quantum mechanics - Thermal de Broglie wavelength ...

https://physics.stackexchange.com/questions/252266/"

There is an introductory paragraph defining the Greek letter lambda and undoubtedly further reading may get you to where you need to go.>

 

[chicopee]

Now check this Wikipedia site

https://en.wikipedia.org/wiki/Thermal_de_Broglie_wavelength

as you will find reference to this statement"...We can take the average interparticle spacing in the gas to be approximately (V/N)1/3 where V is the volume and N is the number of particles…" Perhaps this site will help for further research.

 

[JacobTk]

Thanks for the tips guys, I've found the answer. It is actually extremely simple, the thermal de Broglie volume defined in those papers is the thermal de Broglie wavelength cube.. At the same time it is a very unsatisfying answer because that means that they did not use the cp0 in their ideal gas part Helmholtz energy definition. For most of the calculations it does not matter but if they neglect it they should write it.