Computation of indirect nuclear spin-spin couplings with reduced complexity in pure and hybrid density functional approximations.
Computation of indirect nuclear spin-spin couplings with reduced complexity in pure and hybrid density functional approximations.
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DOI：
10.1063/1.4962260
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发表时间：
2016-09
期刊：
影响因子：
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通讯作者：
A. Luenser;J. Kussmann;C. Ochsenfeld
中科院分区：
文献类型：
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作者：
A. Luenser;J. Kussmann;C. Ochsenfeld
我们提出了一种在Hartree-Fock和Kohn-Sham密度泛函水平上确定间接核自旋-自旋耦合常数的(亚)线性标度算法。利用有效的积分算法和稀疏代数程序，可以得到具有非零HOMO-LUMO间隙的系统的整体(次)线性标度行为。对具有超过1000个原子和20000个基函数的系统的计算表明了我们的参考实现的性能和准确性。具体地说，我们证明了线性代数在10000个及以上基函数的传统算法的运行时间中占据主导地位。对于被测系统，我们的方法在总运行时间上的加速比超过6倍，在线性代数步骤上的加速比超过10倍。此外，本文还研究了氨基吡唑肽在水环境中的自旋-自旋偶联的收敛问题：用新的方法证明了大的溶剂球是收敛自旋-自旋偶联的必要条件。
We present a (sub)linear-scaling algorithm to determine indirect nuclear spin-spin coupling constants at the Hartree-Fock and Kohn-Sham density functional levels of theory. Employing efficient integral algorithms and sparse algebra routines, an overall (sub)linear scaling behavior can be obtained for systems with a non-vanishing HOMO-LUMO gap. Calculations on systems with over 1000 atoms and 20 000 basis functions illustrate the performance and accuracy of our reference implementation. Specifically, we demonstrate that linear algebra dominates the runtime of conventional algorithms for 10 000 basis functions and above. Attainable speedups of our method exceed 6 × in total runtime and 10 × in the linear algebra steps for the tested systems. Furthermore, a convergence study of spin-spin couplings of an aminopyrazole peptide upon inclusion of the water environment is presented: using the new method it is shown that large solvent spheres are necessary to converge spin-spin coupling values.