My guess. Neither a "reverse parabola", which has a maximum, not "linear", which has none are physically reasonable right. Either you are far from the minimum energy, your structure is unstable or something else is wrong. Ensure that you are at a stable minimum before trying to do the elastic constants.
Just my guess based upon what you said in your email. Did you mean "reverse"? --- Professor Laurence Marks Department of Materials Science and Engineering Northwestern University www.numis.northwestern.edu "Research is to see what everybody else has seen, and to think what nobody else has thought" Albert Szent-Györgyi On Sat, Sep 10, 2022, 9:42 AM AJAY SINGH VERMA <ajay_...@hotmail.com> wrote: > Dear Sir, > While running IRelast for the same cubic material, I changed volume > optimization of percentage parameter and also rmt reduction. In results, I > am getting linear curve and reverse parabola. In 4th fitting, result cant > be found for Reuss and Hill elastic constant prediction. Moreover, the > same syntax error is also there. > Kindly help > ------------------------------ > *From:* AJAY SINGH VERMA > *Sent:* Thursday, September 8, 2022 9:03 PM > *To:* wien-requ...@zeus.theochem.tuwien.ac.at < > wien-requ...@zeus.theochem.tuwien.ac.at>; wien zeus < > wien@zeus.theochem.tuwien.ac.at>; m_jama...@yahoo.com <m_jama...@yahoo.com > > > *Subject:* IRelast error in C_ana_elast_lapw > > Dear all, > > While running C_ana_elast_lapw for my compound, I am getting following > error given below in order of fit 4. Result for order 2 and 3 is being > shown properly. Output order file has been attached. > Kindly help. > > > ORDER OF FIT IS : 4 , At volume = 2365.41197 (bohr^3) ######## > (c11-c12) = 175.946 (GPa) > (c11+2c12) = -0.091 (GPa) > (c44) = 1.175 (GPa) > ________________________________________ > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > (standard_in) 1: syntax error > c11 = 117.267 (GPa) > c12 = -58.679 (GPa) > c44 = 1.175 (GPa) > ======================================================================= > > Prediction VOIGT Bulk modulus by using elastic constant values = -.030 > (GPa) > Prediction REUSS Bulk modulus by using elastic constant values = (GPa) > Prediction HILL Bulk modulus by using elastic constant values = (GPa) > > Prediction VOIGT Shear modulus by using elastic constant values = 35.894 > (GPa) > Prediction REUSS Shear modulus by using elastic constant values = (GPa) > Prediction HILL Shear modulus by using elastic constant values = (GPa) > > Prediction VOIGT Young modulus by using elastic constant values = -.270 > (GPa) > Prediction REUSS Young modulus by using elastic constant values = (GPa) > Prediction HILL Young modulus by using elastic constant values = (GPa) > > Prediction VOIGT Poisson's coefficient by using elastic constant values = > -1.003 > Prediction REUSS Poisson's coefficient by using elastic constant values = > Prediction HILL Poisson's coefficient by using elastic constant values = > > You can find these data in the output-order file. > > > Thanks and Regards. > > _______________________________________________ > Wien mailing list > Wien@zeus.theochem.tuwien.ac.at > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien > SEARCH the MAILING-LIST at: > http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html >
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