Potential Energy Curve for Ammonia Inversion?

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Discussion Overview

The discussion revolves around the potential energy curve for ammonia inversion, specifically in the context of a Quantum II class paper on masers. Participants explore the need for data points on the inversion potential energy curve along the Nitrogen inversion axis and discuss numerical methods for finding roots of transcendental equations related to this model.

Discussion Character

  • Exploratory, Technical explanation, Homework-related, Mathematical reasoning

Main Points Raised

  • One participant seeks a graph or data points for the inversion potential energy curve of ammonia, mentioning a naive model involving coupled infinite potential wells.
  • Another participant suggests using built-in numerical calculation functions in the programming language being used, noting that finding roots of transcendental equations may require multiple starting points if the functions are complex.
  • A participant inquires about the suitability of Mathematica's #FindRoot function for their needs.
  • It is proposed that the user should test #FindRoot with sample functions to verify its effectiveness for their specific requirements.

Areas of Agreement / Disagreement

Participants generally agree on the need for numerical methods to find roots of transcendental equations, but there is no consensus on the specific approach or data sources for the potential energy curve.

Contextual Notes

The discussion does not resolve the specific data requirements for the potential energy curve or the effectiveness of the proposed numerical methods, leaving these aspects open for further exploration.

Who May Find This Useful

Students and researchers interested in quantum mechanics, maser technology, and numerical methods for solving transcendental equations may find this discussion relevant.

kq6up
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For my Quantum II class I am working on a paper about masers. I am using a naive model (a coupled pair of infinite potential wells), and I would like to find out where I can find a graph of the inversion potential energy curve. This would be a simple one dimensional curve of the potential along the Nitrogen inversion axis. If one googles Ammonia maser, a qualitative curve can easily be found, but I have been unsuccessful in finding a graph that actually has data points on it. A set of points would be fine too. My end game is using this data to find the partition size in the middle. I am going to use a potential energy partition for the wells that has a full maximum values but the width set at half the height of the real curve. The solution for my model is the value of the wave number ##k## for a pair of transcendental equations that have a family of roots where n=1,2,3, etc. The ##k##'s can be use to calculate the transition energy between even and odd parity states, and hopefully this energy will be somewhat closely correspond to a 24GHz frequency , and hopeWhat numerical calculation function would be best for finding roots of transcendentals involving trig and hyperbolic trig functions?

Thanks,
KQ6UP
 
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kq6up said:
What numerical calculation function would be best for finding roots of transcendentals involving trig and hyperbolic trig functions?
The built-in ones in the programming languague you are using. There is nothing special about transcendentals. If the functions are wiggly you may need several starting points to find all the roots (or even one).

For finding the data go back to early papers on the subject and look at what they used. Or find a reasonably recent paper and write a polite email to its youngest author.
 
I was planning on just using Mathematica. Is #FindRoot a good one?

Thanks,
KQ6UP
 
kq6up said:
Is #FindRoot a good one?
You can check by creating some test functions of the kind you will need, plot them, and visually check whether the output of #FindRoot matches your requirements.
 
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Perfect, thank you.

KQ6UP
 

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