Otter
Electronic and ionic structure for dense plasmas
Otter is a Python package for average-atom, pseudoatom, and integral-equation calculations in warm and hot dense matter. Starting from a composition, mass density, and temperature, it can calculate electronic density components, pseudoatom screening clouds, effective ion–ion potentials, pair distribution functions \(g_{ij}(r)\), and static structure factors \(S_{ij}(k)\).
Otter is based primarily on the pseudoatom model of Starrett and Saumon (2014).
Where to begin
Installation describes the locked source installation.
Quick start introduces the unified plasma workflow.
User guide explains portable state files and analysis workflows.
Scientific benchmarks records reproducible comparisons with published data.
API reference documents the stable public Python interface.
Capabilities
finite-temperature quantum and Thomas–Fermi electronic structure; the quantum model provides orbital levels, occupations, and density components;
pseudoatom densities \(n_{\mathrm{ion}}(r)\) and \(n_{\mathrm{scr}}(r)\), with form factors \(f(k)=n_{\mathrm{ion}}(k)\) and \(q(k)=n_{\mathrm{scr}}(k)\);
effective ion–ion potentials \(V_{ab}(r)\) and \(V_{ab}(k)\);
one- and multicomponent QOZ/HNC results \(g_{ij}(r)\) and \(S_{ij}(k)\).
Getting started
Physics and validation
Reference