Hi Abhjeet, I think you're misunderstanding the meaning of alpha here. It's not the temperature expansion coefficient; after all, you're measuring at only one temperature. Generally alpha and thetad should be guessed. For a variety of reasons, they are unlikely to be exactly the same as the literature values when you fit them. For one thing, the Debye model is just that-- a model--and therefore different methods of determining the Debye temperature will yield somewhat different results. As far as the extended parameters Ei, third, and fourth, are you saying you'd like to fit them but can't figure out how to do it? Or that you're wondering how to set them? --Scott Calvin Sarah Lawrence College On Feb 2, 2009, at 3:32 AM, abhijeet gaur wrote:
Hi everyone,
I am giving artemis the following parameters:
guess amp 1 def delr alpha*reff guess enot 0 def ss debye(temp,thetad) set alpha .0002 set thetad 343 set temp 298 But I am not getting a very good fit. The value of debye temperature is 343 for Cu( Kittel book) but I got to know that some persons even guessed the value of thetad as 285+-16 . I am not getting that how we can guess the value of alpha and thetad . Also I am not getting the value of Ei, 3rd and 4th cumulant in the fit results . So How can I get the value of these parameters in the fit results . With thanks Abhijeet Gaur
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