This paper summarises the theory and functionality behind Questaal, an open-source suite of codes for calculating the electronic structure and related properties of materials from first principles. The formalism of the linearised muffin-tin orbital (LMTO) method is revisited in detail and developed further by the introduction of short-ranged tight-binding basis functions for full-potential calculations. The LMTO method is presented in both Green's function and wave function formulations for bulk and layered systems. The suite's full-potential LMTO code uses a sophisticated basis and augmentation method that allows an efficient and precise solution to the band problem at different levels of theory, most importantly density functional theory, LDA+U, quasi-particle self-consistent GW and combinations of these with dynamical mean field theory. This paper details the technical and theoretical bases of these methods, their implementation in Questaal, and provides an overview of the code's design and capabilities.

中文翻译：

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Questaal：基于线性松饼锡轨道技术的电子结构方法包

本文总结了 Questaal 背后的理论和功能，Questaal 是一套开源代码，用于从第一原理计算材料的电子结构和相关属性。通过引入用于全电位计算的短程紧束缚基函数，详细重新审视了线性化松饼锡轨道 (LMTO) 方法的形式化并进一步发展。LMTO 方法在体和层状系统的格林函数和波函数公式中都有介绍。该套件的全势 LMTO 代码使用复杂的基础和增强方法，可以在不同理论水平（最重要的是密度泛函理论、LDA+U、准粒子自洽 GW 和组合）上高效精确地解决能带问题这些与动态平均场理论。