Partition Function of CO2 at 1000K - Database?

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Discussion Overview

The discussion centers on the existence of a database for the partition function of CO2 at various temperatures, specifically at 1000K. Participants explore the nature of the partition function, its dependence on temperature, and the parameters involved in its calculation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about a database for the partition function at different temperatures, suggesting it varies only with temperature.
  • Another participant clarifies that the partition function, denoted as Q=Q(N,V,T), does not solely depend on temperature.
  • A different participant speculates that the original inquiry might have intended to refer to the partition coefficient instead.
  • A later reply discusses the total partition function or state sum, referencing a book that states it depends on temperature and provides expressions for vibrational, rotational, and electronic partition functions that require additional parameters.
  • This participant expresses a belief that the partition function is consistent across species, with variations in energy level populations due to temperature, although they acknowledge the possibility of being incorrect.
  • Another participant mentions discovering a file (TIPS) that generates partition function values for different species and isotopes using the HITRAN database, which is fitted with Lagrange 4 points fitting based on temperature input.

Areas of Agreement / Disagreement

Participants express differing views on the dependence of the partition function on temperature and other parameters, indicating that multiple competing perspectives exist without a clear consensus.

Contextual Notes

Some assumptions regarding the definitions and calculations of the partition function remain unresolved, particularly concerning its dependence on temperature and the parameters involved in its determination.

nordmoon
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Does there exist a database for the Partition function at different temperatures? As I understand it it only varies with temperature and is otherwise the same for the species. I am looking for the partition function for C02 at T=1000K.
 
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Recall that the (canonical) partition function, Q=Q(N,V,T), i.e. no it does not only vary with temperature.
 
Maybe he intended partition coefficient?
 
The total "partition function" or "state sum" of the molecule is what I meant. According to the book "Spectrophysics" by A. Thorne, U. Litzen, S. Johnsson (and other books in molecular and atomic spectroscopy) the partition function only depends on temperature (i.e. is a function of T). At least they write Q(T) in the book?? There are expressions for the vibrational, rotational and electronic partition functions which can be approximated to something that requires some other parameters like vibrational constant, rotational constant and such. But again, this is not the total internal state sum. My understanding is that the partition function is the same for each species (there are same amounts of energy levels in the atom or molecule) and that only changes is the population of these levels with the temperature and thus it only varies on the temperature?? But I could be wrong...

Today I actually found a file (TIPS) which produces the partition function values for different species and isotopes in the hitran database (which they have obtained and is fitted with Lagrange 4 points fitting) with the input of the temperature.

Thank you all for trying to help me.
 

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