<div><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">Dear Wien2k users,<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p></SPAN></div> <div><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'"> <o:p></o:p></SPAN></div> <div><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">I am facing a problem in optimization and mini due to RMT. I want to optimize a crystal structure of AB2 compound. I optimized the parameter RKmax, Kmesh, RMT, etc., and run the SCF calculation. After seeing its force, which is higher than 5mRy/atom, i did the mini calculation. I got the stop error due to overlapping of sphere.<SPAN style="mso-spacerun: yes"> </SPAN>I changed the RMT of A and B from 2.2 to 2. <SPAN style="mso-spacerun: yes"> </SPAN>Now for the new RMT, I optimized Kmesh and RKmax value. Then, the calculation runs successfully and the force is also reduced
around 1mRy/atom. The next step, I did optimization job <SPAN style="mso-spacerun: yes"> </SPAN>(with mini –I –j “run_lapw –I –fc 1 –I 100” ) with varying volume from -2% to +2%.<SPAN style="mso-spacerun: yes"> </SPAN>It gives error due to overlapping of spheres even with -2% of volume changes.<SPAN style="mso-spacerun: yes"> </SPAN>For -1% volume also showed the same error. Then I tried with varying volume from -0.5 % to +0.5 % volume. The energy values decreases from +0.5% to –O.5%.<SPAN style="mso-spacerun: yes"> </SPAN>But I didn’t get the parabola.<SPAN style="mso-spacerun: yes"> </SPAN><SPAN style="mso-spacerun: yes"> </SPAN><o:p></o:p></SPAN></div> <div><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'"><o:p> </o:p></SPAN></div> <div><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">Because of the above result, I am expecting the minimum energy configuration will be less than +0.5% volume
change.<SPAN style="mso-spacerun: yes"> </SPAN><o:p></o:p></SPAN></div> <div><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'"><o:p> </o:p></SPAN></div> <div><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">This is the current situation.<SPAN style="mso-spacerun: yes"> </SPAN>Further I have to reduce the RMT value or to change the reduced RMT (which I gave 3% reduction) value?<o:p></o:p></SPAN></div> <div><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'"><o:p> </o:p></SPAN></div> <div><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">Before going to scf calculation, is there any possibility or a thumb rule to find the approximate RMT value for corresponding crystal structure? <SPAN style="mso-spacerun: yes"> </SPAN>Because it is time consuming process, do find the appropriate RMT after mini.<o:p></o:p></SPAN></div> <div><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY:
'Arial','sans-serif'"><o:p> </o:p></SPAN></div> <div><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: 'Arial','sans-serif'">If the system have force greater than 5 mRy/atom, first I have do the mini then optimize the structure with varying volume or find the minimum energy configuration structure by varying volume and do the mini for that corresponding structure?<o:p></o:p></SPAN></div> <div> </div><BR><BR><p>Regards,</p><p>Santhy Jaiker<br style="COLOR:rgb(191,95,0);"><span style="COLOR:rgb(185,185,185);">**********************************************</span><br style="COLOR:rgb(185,185,185);"><span style="COLOR:rgb(185,185,185);">A truly happy person is one</span><br style="COLOR:rgb(185,185,185);"><span style="COLOR:rgb(185,185,185);">who can enjoy the scenery on a detour</span><br style="COLOR:rgb(185,185,185);"><span style="COLOR:rgb(185,185,185);">**********************************************</span><br></p><p> 
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