报告题目： The basis set limit is no longera chimera: DFT energy and properties with multiwavelets
报告人： Luca Frediani ,Associate Professor University of Tromsø，Norway
报告时间：2016年10月10日（周一）15:00
报告地点：逸夫楼C座314会议室
摘要：
The accuracy of DensityFunctional Theory calculations is essentially governed by two factors: thechosen functional and the size of the employed basis.The quest for“thefunctional” has reveled extremelychallenging. Despite the great popularity and success of some very well knownfunctionals, the universal functional remains elusive and a vast choice offunctional is currently available, sometimes tailor-made to target specificsystems or properties. Assessing the accuracy of a modern functional, requiresalso a basis set which is capable of achieving an even greater precision –ideally approaching a complete basis – efficiently andsystematically.The two main families of basis sets (plane waves andGaussian-type orbitals) are have drawbacks which limit them, especially whenhigh precision is required. A very attractive alternative is constituted by bygrid-base methods such as Multiwavelets. They combine conceptual simplicity(basis functions are simple polynomials) with the ability to reach completebasis set results within any given, predefined precision. Multiwavelets arefully orthonormal (like plane waves) and localized (likeGaussian-typeorbitals).MRChem,our recently developed multiwavelet code is capable of runningSCF calculations (HF and DFT) of energy and molecular properties. We will herepresent the theoretical Multiwavelet framework, with emphasis on ourimplementation of the SCF optimizations and linear response solver. Such animplementation has been recently adopted to obtain the atomization energy ofmore than 200 substrates with unprecedented and guaranteed micro-Hartreeaccuracy. We have also obtained magnetizability tensors and shielding constantsof 28 substrates with 3-4 digits accuracy. Such results allowed us to assessthe quality of some widely used functionals, to benchmark the accuracy of someof the most commonly used basis sets and related extrapolation methods.Inaddition to the theoretical framework and the recent results, emphasis will begiven to the computational aspects of the multiwavelet framework and thechallenges which must be overcome to make the framework accessible for large(1000 electrons or more) systems.
Researchinterests
Wavelet and Multiwavelet Methods in Theoretical Chemistry,
Molecular Properties.
Solvent Effects
QM/MM Methods
Selected Publications:
1．R. Di Remigio, R.Bast, and L. Frediani, “4-ComponentRelativistic Calculations in Solution with the PolarizableContinuum Model ofSolvation: Theory, Implementation and Application to the Group 16 . . . ”, The Journal of Physical Chemistry(2014) 10.1021/jp507279y.
2．A. Durdek, S. R.Jensen, J. Juselius, P. Wind, T. Flå, and L. Frediani, “Adaptive order polynomialalgorithm in amulti-wavelet representation scheme”, Applied Numerical Mathematics(2014).
3．K. H. Hopmann, L.Frediani, and A. Bayer, “Iridium-PHOX-MediatedAlkene Hydrogenation: Isomerization Influences the Stereochemical Outcome”, Organometallics 33, 2790–2797 (2014).
4．S. R. Jensen, J. Juselius, A. Durdek, T. Flå, P. Wind, and L. Frediani, “Linear scaling Coulomb interaction in the multiwaveletbasis, a parallel implementation”,Int. J. Model. Simul. Sci. Comput., 1441003 (2014).