Dear Pandey, A good place to start is for example a unitcell of 8 atom with ibrav=1. ATOMIC_POSITIONS Si 0.000 0.000 0.000 Si 0.500 0.500 0.000 Si 0.500 0.000 0.500 Si 0.000 0.500 0.500 Si 0.250 0.250 0.250 Si 0.750 0.750 0.250 Si 0.750 0.250 0.750 Si 0.250 0.750 0.750
The you can either use pen and paper to expand it to 2x2x2 supercell or if you dont want to do that, you can just used other softwares like VESTA or GDIS to make your self. I have never come acorss the same errors as you have when doing calculations on the Si. To use GDIS you need to save the sttructure in Fractional coordinates. Kind Regards ============================================== OUMA, Cecil Naphtaly Moro PhD. Student Physics Department, University of Pretoria, South Africa Private bag X20 Hatfield Pretoria 0028 Office 5-61, NW-1 Building Cell: +27 721385182 ============================================== "Clouds are not spheres, mountains are not cones, coastlines are not circles,and bark is not smooth, nor does lightning travel in a straight line." - Benoit Mandelbrot * The more progress physical sciences make, the more they tend to enter the domain of mathematics, which is a kind of centre to which they all converge. We may even judge the degree of perfection to which a science has arrived by the facility with which it may be submitted to calculation. Quoted in E Mailly, **Eulogy on Quetelet 1874 * -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120216/caf527d8/attachment.htm
