Repisky Michal, Komorovsky Stanislav, Kadek Marius, Konecny Lukas, Ekström Ulf, Malkin Elena, Kaupp Martin, Ruud Kenneth, Malkina Olga L, Malkin Vladimir G
Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, UiT The Arctic University of Norway, N-9037 Tromsø, Norway.
Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dubravska cesta 9, SK-84536 Bratislava, Slovakia.
J Chem Phys. 2020 May 14;152(18):184101. doi: 10.1063/5.0005094.
With the increasing interest in compounds containing heavier elements, the experimental and theoretical community requires computationally efficient approaches capable of simultaneous non-perturbative treatment of relativistic, spin-polarization, and electron correlation effects. The ReSpect program has been designed with this goal in mind and developed to perform relativistic density functional theory (DFT) calculations on molecules and solids at the quasirelativistic two-component (X2C Hamiltonian) and fully relativistic four-component (Dirac-Coulomb Hamiltonian) level of theory, including the effects of spin polarization in open-shell systems at the Kramers-unrestricted self-consistent field level. Through efficient algorithms exploiting time-reversal symmetry, biquaternion algebra, and the locality of atom-centered Gaussian-type orbitals, a significant reduction of the methodological complexity and computational cost has been achieved. This article summarizes the essential theoretical and technical advances made in the program, supplemented by example calculations. ReSpect allows molecules with >100 atoms to be efficiently handled at the four-component level of theory on standard central processing unit-based commodity clusters, at computational costs that rarely exceed a factor of 10 when compared to the non-relativistic realm. In addition to the prediction of band structures in solids, ReSpect offers a growing list of molecular spectroscopic parameters that range from electron paramagnetic resonance parameters (g-tensor, A-tensor, and zero-field splitting), via (p)NMR chemical shifts and nuclear spin-spin couplings, to various linear response properties using either conventional or damped-response time-dependent DFT (TDDFT): excitation energies, frequency-dependent polarizabilities, and natural chiroptical properties (electronic circular dichroism and optical rotatory dispersion). In addition, relativistic real-time TDDFT electron dynamics is another unique feature of the program. Documentation, including user manuals and tutorials, is available at the program's website http://www.respectprogram.org.
随着对含重元素化合物的兴趣日益增加，实验和理论界需要能够同时对相对论效应、自旋极化和电子相关效应进行非微扰处理的高效计算方法。ReSpect程序就是基于这一目标设计并开发的，用于在准相对论双分量（X2C哈密顿量）和全相对论四分量（狄拉克-库仑哈密顿量）理论水平上对分子和固体进行相对论密度泛函理论（DFT）计算，包括在克莱默斯无限制自洽场水平下开壳层系统中的自旋极化效应。通过利用时间反演对称性、双四元数代数以及以原子为中心的高斯型轨道的局部性的高效算法，实现了方法复杂性和计算成本的显著降低。本文总结了该程序取得的重要理论和技术进展，并辅以示例计算。ReSpect能够在基于标准中央处理器的商用集群上，以四分量理论水平高效处理含100多个原子的分子，与非相对论领域相比，计算成本很少超过10倍。除了预测固体中的能带结构外，ReSpect还提供了越来越多的分子光谱参数，范围从电子顺磁共振参数（g张量、A张量和零场分裂），到（p）NMR化学位移和核自旋-自旋耦合，再到使用传统或阻尼响应含时DFT（TDDFT）的各种线性响应性质：激发能、频率相关极化率和自然手性光学性质（电子圆二色性和旋光色散）。此外，相对论实时TDDFT电子动力学是该程序的另一个独特功能。该程序的文档，包括用户手册和教程，可在其网站http://www.respectprogram.org上获取。
