> Hello all, > > I have a question concerning the broadening parameter within the PDOS > block. I understand that the larger this value, > the smoother the resulting PDOS curve
Dear Tom, this is correct. > and the larger the possibility one loses information concerning > peaks that may have been smoothed over. This depends on your definition of "one loses". No peak loses its spectral weight on broadening, but might cease to exist as a separate feature. The question is whether you want it or not. In principle the broadening has two aims: 1. In an absence of tetrahedron integration in Siesta, to imitate a continuous DOS of a solid, in place of a bunch of delta-peaks as it comes out from a calculation; 2. To suppress excessive but less informative, often spurious, features, in the DOS, to provide a more obvious comparison with other calculations, or with experimantal spectra. So the selection of broadening parameter is your free choice and really depends on what you want to emphasize in your DOS plots. > Ideally, one would want this to be as small as possible. > Is there anything wrong with this assumption. Only that you may end up with a forest of delta-peaks, not necessarily much instructive. After all, if you care about the exact positions of certain discrete levels (say, in a molecle), you have them directly from the calculation and do not need to broaden them first with infinitely small broadening parameter. > To put > it another way, is there any danger to setting this parameter really low, > say 0.05 for example. This is first of all related to the energy step and the energy window in your DOS plot! Everything is relative... Best regards Andrei interval > > > > Thanks in advance, > > > Tom > > _________________________________________________________________ > Stay organized with simple drag and drop from Windows Live Hotmail. > http://windowslive.com/Explore/hotmail?ocid=TXT_TAGLM_WL_hotmail_102008
