Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Thermal de Broglie volume

Thermal de Broglie volume

Thermal de Broglie volume


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!

RE: Thermal de Broglie volume

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.

RE: Thermal de Broglie volume

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

RE: Thermal de Broglie volume

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,

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

RE: Thermal de Broglie volume

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.>

RE: Thermal de Broglie volume

Now check this Wikipedia site https://en.wikipedia.org/wiki/Thermal_de_Broglie_w... 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.

RE: Thermal de Broglie volume

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.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close