QUantum Electronic STructure

SeqQuest Electronic Structure Code

SeqQuest is a general-purpose electronic structure code to compute energies and forces for periodic surfaces (slabs) or solids, or finite molecules. SeqQuest uses density functional theory (DFT), and is capable of calculations using either LDA or GGA, with or without spin-polarization. It will do energy minimization of atomic positions through force elimination, cell shape optimization by stress-elimination, and molecular dynamics. SeqQuest rigorously and automatically corrects for supercell effects using the Local Moment Counter Charge method. SeqQuest uses norm-conserving pseudopotentials and high-quality contracted-Gaussian basis sets in a “Linear Combination of Atomic Orbitals” (LCAO) approach in its description of the electronic structure, and is a very efficient, compact code that enables very large-scale calculations (100’s, even 1000+ atoms on large memory workstations) using rather modest computational resources (single-processor work stations, or small clusters). Key to this performance is the implementation of highly efficient algorithms for the generation of the Hamiltonian matrix that scale linearly with problem size.

SeqQuest is actively under development at Sandia National Laboratories, within the Multiscale Science Dept. (1444). The Quest effort owes thanks to many.

SeqQuest is being made available to the wider research community as a computational tool installed in the NSF nanoHUB web portal at Purdue and the memsHUB web portal. SeqQuest is currently only licensed to “friendly users”, and is being made available to a wider audience soon.

More information about use of the code can be found in the following: