Is there a formula for the temperature dependence of Debye temperature?

In summary, the Debye temperature is temperature dependent on the material/element. The Debye temperature can be estimated from the material dependent variables.
  • #1
hugonot
7
0
I guess is Debye temperature dependent on temperature? I.e TD(T)?
Does anybody know a theoretical formula for temperature dependence of Debye temperature?:confused:
 
Last edited:
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  • #3
Thanks, However, I know this references.
My problem is:
I have got specific temperature dependence C(T) for the solid compound.
I can estimate Debye temperature from the fit, but it will be only one value for the whole range of temperatures.
How can I estimate Debye temperature at specific temperature?
How can t be estimated from material dependent variables? I know the formula for TD http://en.wikipedia.org/wiki/Debye_model but what should I use as N and V?
If V stands for volume, what means N or rather how to calculate it?
Could you give me an example? I mixed up :confused:
 
  • #4
hugonot said:
Thanks, However, I know this references.
My problem is:
I have got specific temperature dependence C(T) for the solid compound.
I can estimate Debye temperature from the fit, but it will be only one value for the whole range of temperatures.
How can I estimate Debye temperature at specific temperature?
How can t be estimated from material dependent variables? I know the formula for TD http://en.wikipedia.org/wiki/Debye_model but what should I use as N and V?
If V stands for volume, what means N or rather how to calculate it?
Could you give me an example? I mixed up :confused:
In the Wikipedia article cited - http://en.wikipedia.org/wiki/Debye_model#Debye.27s_derivation - N is the number of atoms.

If the atomic density is given by [itex]\rho[/itex]NA/A, where [itex]\rho[/itex] is the density, NA is Avogadro's number, A is the atomic mass.
 
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  • #5
hugonot said:
I guess is Debye temperature dependent on temperature? I.e TD(T)?
Does anybody know a theoretical formula for temperature dependence of Debye temperature?:confused:
Any temperature dependence in the Debye Temperature comes from temperature dependences in elastic constants (and due to thermal expansion). These changes are small: about 1 part in 1000 to 1000,000 per Kelvin.
 
  • #6
Thanks for both responses.
I have still a problem with N/V (number per atoms in unit volume).
I have got elementary cell volume V and mass weight of the molecule M.
The cryst. group is P1-. I don't have density,
How can I calculate N/V?
 
  • #7
hugonot said:
Thanks for both responses.
I have still a problem with N/V (number per atoms in unit volume).
I have got elementary cell volume V and mass weight of the molecule M.
The cryst. group is P1-. I don't have density,
How can I calculate N/V?
What type of molecule, i.e. is this a mineral or alloy?

For some basic lattices, there is usually a given number of atoms/cell and a unit cell volume based on the geometry and lattice parameters. It's a close estimate to get N/V, if one doesn't have mass density.
 
  • #8
My molecule is organic compound - benzene derivative, I visualised elementary cell but
it seems complicated to calculate the number of atoms...
I have got cell parameters.
 
  • #9
Where can I find a procedure for Debye model evaluation or tables of this integral value?
I have found a reference to the tables by HARRISON but not available for me...
 

1. What is the Debye temperature formula?

The Debye temperature formula is a mathematical equation used to calculate the characteristic temperature of a solid material. It is named after Peter Debye, a physicist who proposed the concept of a "Debye solid" in the early 20th century.

2. How is the Debye temperature formula calculated?

The Debye temperature formula is calculated by taking into account the density and elastic properties of a material. It is expressed as: ΘD = (h / kB) * (3N / 4πV)^(1/3) * (vs^3 / vl^3), where h is Planck's constant, kB is the Boltzmann constant, N is the number of atoms per unit volume, V is the volume of the unit cell, vs is the speed of sound in the solid, and vl is the speed of longitudinal sound waves.

3. What is the significance of the Debye temperature?

The Debye temperature is a measure of the average energy or temperature of the lattice vibrations in a solid. It is used to describe the thermal and elastic properties of materials, and can also provide insights into the structural and electronic properties of a material.

4. How does the Debye temperature vary with different materials?

The Debye temperature can vary greatly with different materials, depending on their density, elasticity, and crystal structure. Generally, metals tend to have higher Debye temperatures than non-metals, and materials with stronger bonds tend to have higher Debye temperatures than those with weaker bonds.

5. What are some real-world applications of the Debye temperature formula?

The Debye temperature formula is used in various fields such as materials science, condensed matter physics, and geophysics. It is utilized in the study of thermal and mechanical properties of materials, as well as in the design and development of new materials for specific applications. It also has applications in geophysics, where it is used to understand the thermal properties of Earth's interior and the behavior of materials under extreme conditions.

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