Actually, the manual is pretty clear on this one: if the lattice vectors are not specified, SIESTA uses the smallest possible cell that ensures no basis function overlap with the images of your system plus 10%.
2007/8/15, vikas thakur <[EMAIL PROTECTED]>: > > Dear Ian, > I think if you do not specify lattice vectors siesta will take default > which is 1 0 0 , 0 1 0 , 0 0 1 . In this case if you choose small lattice > constant then siesta definatly repeat unit cell. But as per my > understanding if your lattice constant is too much large so that there is no > effect of another adjecent unit cell (assume if it is present) then sista > will not repeat the unit cell. > The best way is specify your lattice constant as you have and then give > lattice parameters as large so that adjecent unit cell ( assume if it is > present ) do not have any effect . > for example if your lattice constent is 4.26 Ang then specify Lattice > vectors as > 20 0 0 , 0 20 0 , 0 0 20. It will not repeat the cell. > > Dear all Please clear me this concept if i am wrong. > > *Ian Shuttleworth <[EMAIL PROTECTED]>* wrote: > > If the block LatticeVectors is not specified does siesta assume that the > unit is not repeating, that is, it's just a free standing molecule or > cluster and that there are no adjacent cells? > > Has anyone got any experience of modelling these finite units (in > particular clusters) and comments about how periodicity is treated by > siesta in these systems? > > Thanks > > Ian Shuttleworth > > > ------------------------------ > Take the Internet to Go: Yahoo!Go puts the Internet in your > pocket:<http://us.rd.yahoo.com/evt=48253/*http://mobile.yahoo.com/go?refer=1GNXIC>mail, > news, photos & more. > >
