Report on Workshop "Hands-on-FPLO"
March 3 to 7, 2002, IFW Dresden
Supported by ESF, STRUC-Ok Programme
1. Scientific content of the event
From March 3 to 7, 2002, IFW Dresden hosted the workshop "Hands-on-FPLO" that was supported by the ESF, STRUC V)k. Purpose of the tutorial workshop was to provide an introduction into the concept, the code, and the handling of the FPLO package including the ability to cope with simple problems that may arise when using the code.
This package is a Full-Potential Local-Orbital minimum-basis code [1] to solve the Kohn-Sham equations in a regular lattice by using the local density approximation. The situation of a chemically disordered structure is covered by an implemented CPA (coherent potential approximation) solver [2]. Relativistic effects can be treated in a related 4-component code that solves the Kohn-Sham-Dirac equations (RFPLO) [3], and the LSDA+U formalism is currently being implemented. Much effort has been spent in the mentioned methods to achieve a level of numerical accuracy which is comparabel to advanced full-potential LAPW implementations, though the basis set is almost one order of magnitude smaller. In particular, the absolute values of the total energy were found to agree with the results of the FLAPW package WIEN-97 within about 1 mHartree per atom for non-relativistic calculations [1]. The agreement with respect to lattice parameters and bulk moduli is better than within 0.5 and 10 complementary. While WIENxx in most cases still sets the accuracy standard, a major advantage of the FPLO package is its minimum basis concept. It makes highly accurate full-potential calculations for elementary cells of up to 100 transition metal atoms feasible and is a good starting point for approaches beyond the local density approximation.
The workshop programme consisted of lectures held by the code developers and by experiences users of the code primarily in the morning hours, and exercises in the afternoon. While the first exercise was focussed on "getting started" (fcc-aluminium: how to create the input file, meaning and handling of the output), all participants were able to work on systems of their individual choice during the second and third day of the workshop. The number of participants (30 trainees and 11 lecturers) was almost twice the originally planned number, demonstrating the need of fast and accurate DFT code. Twelve X-terminals, each connected to a separate dual node of our LINUX cluster, were available to the participants. In this way, the group size could be kept moderately small and (almost) individual work was possible.
More details may be found in newsletter 51 from page 55