I think order doesn't matter. It's a simple concept. If energy of individual atoms is more than the compound, the compound is more stable and vice-versa.
On Nov 14, 2017 19:01, "Saif Ullah" <[email protected]> wrote: > I'm not aware of the system under study, but if it is a new material, then > one should calculate phonons to check the stability. > > If the system is already synthesized and you are studying the effect of > doping/adsorption, then binding/formation/cohesive/adsorption energy(ies) > is(are) enough. > > Also, keep in mind that the value (-/+) depends on the order of the > equation. > > Regards > Saif > Dept. Physics, UFJF, Brazil > > On Tue, Nov 14, 2017 at 8:26 AM, Rajesh <[email protected]> > wrote: > >> Dear Saif Ullah, >> The negative value of binding energy is not enough to predict stability? >> Why do we need phonon calculations for that? >> >> On Tue, Nov 14, 2017 at 2:37 PM, Saif Ullah <[email protected]> >> wrote: >> >>> Dear, >>> >>> Ebin = Etot - ENi - EBi - 3EO >>> >>> Or depends on how you write. >>> >>> For stability, you need to calculate phonons. >>> >>> Regards >>> Saif >>> Dept. Physics, UFJF, Brazil >>> >>> On 14 Nov 2017 6:51 am, "Sudha Priyanka" <[email protected]> >>> wrote: >>> >>>> Can anyone suggest how to calculate binding energy of my crystal NaBiO3 >>>> by using Quantum Espresso? >>>> >>>> I have successfully completed the SCF of NaBiO3 using GGA-PBE. I have >>>> checked the SCF file and found the energy value : -333.03842 Ry/unit cell. >>>> >>>> I have performed total energy calculation of isolated atoms Na, Bi and >>>> O and found energy value as -192.232097 Ry, -141.20403847 Ry, -126.84166 Ry >>>> respectively. >>>> >>>> Now, please guide me how to calculate the binding energy of NaBiO3. >>>> >>>> Also I would like to know what should be the binding energy value for a >>>> crystal to be stable? It should be positive or negative value? >>>> >>>> Please suggests formula to calculate binding energy for this perovskite >>>> and suggest me some link or any related papers. >>>> >>>> Your help will be appreciated >>>> >>>> Thanks in advance >>>> >>>> Sudha Priyanka >>>> >>>> >>>> >>>> _______________________________________________ >>>> Pw_forum mailing list >>>> [email protected] >>>> http://pwscf.org/mailman/listinfo/pw_forum >>>> >>> >>> _______________________________________________ >>> Pw_forum mailing list >>> [email protected] >>> http://pwscf.org/mailman/listinfo/pw_forum >>> >> >> >> _______________________________________________ >> Pw_forum mailing list >> [email protected] >> http://pwscf.org/mailman/listinfo/pw_forum >> > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
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