scholarly journals Property-Optimized Gaussian Basis Sets for Lanthanides

2021 ◽  
Author(s):  
Dmitrij Rappoport
Keyword(s):  
Basis Set ◽  
Oxidation States ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Test Set ◽  
Valence Basis Sets ◽  
Triple Zeta ◽  
Lanthanide Atoms ◽  
Split Valence ◽  
Quadruple Zeta

Property-optimized Gaussian basis sets of split-valence, triple-zeta and quadruple-zeta valence quality are developed for the lanthanides Ce–Lu for use with small-core relativistic effective core potentials. They are constructed in a systematic fashion by augmenting def2 orbital basis sets with diffuse basis functions and minimizing negative static isotropic polarizabilities of lanthanide atoms with respect to basis set exponents within the unrestricted Hartree–Fock method. The basis set quality is assessed using a test set of 70 molecules containing the lanthanides in their common oxidation states and f electron occupations. 5d orbital occupation turns out to be the determining factor for the basis set convergence of polarizabilities in lanthanide atoms and the molecular test set. Therefore, two series of property-optimized basis sets are defined. The augmented def2-SVPD, def2-TZVPPD, and def2-QZVPPD basis sets balance the accuracy of polarizabilities across lanthanide oxidation states. The relative errors in atomic and molecular polarizability calculations are ≤8% for augmented split-valence basis sets, ≤2.5% for augmented triple-zeta valence basis sets, and ≤1% for augmented quadruple-zeta valence basis sets. In addition, extended def2-TZVPPDD and def2-QZVPPDD are provided for accurate calculations of lanthanide atoms and neutral clusters. The property-optimized basis sets developed in this work are shown to accurately reproduce electronic absorption spectra of a series of LnCp'3- complexes (Cp' = C5H4SiMe3, Ln = Ce–Nd, Sm) with time-dependent density functional theory.

Molecular orbital and 1H nuclear magnetic resonance studies of the inversion potentials of thianthrene and thioxanthene

1991 ◽  
Vol 69 (6) ◽  
pp. 927-933 ◽  
Author(s):  
Ted Schaefer ◽  
Rudy Sebastian ◽  
Christian Beaulieu
Keyword(s):  
Long Range ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Basis Set ◽  
Basis Sets ◽  
Inversion Barrier ◽  
H Nmr ◽  
Methylene Groups ◽  
Spin Spin Coupling ◽  
Split Valence

The inversion potentials, obtained from STO-3G, STO-3G(*), 3-21G, 3-21G(*), and 4-31G basis sets, are reported for thianthrene and thioxanthene, molecules in which both or only one of the methylene groups have been replaced by sulfur in 9,10-dihydroanthracene. Comparison with the available experimental data suggests that the split-valence bases lead to an overestimate, possibly by about 10 kJ/mol, of the inversion barrier in the crystal, whereas the STO-3G and STO-3G* basis sets underestimate this barrier. It appears that the inversion barrier for thianthrene is much lower in solution than in the crystal. The long-range coupling constants between the methylene and ring protons for thioxanthene in solution are consistent with an inversion barrier somewhat smaller than those obtained with the split-valence bases but rather larger than those predicted with the STO-3G basis set. The bond lengths and angles in the equilibrium structures of the two molecules, as computed with the 3-21G(*) basis, agree reasonably well with those in their crystals, except that the theoretical folding angles are smaller than measured. These discrepancies become less marked when expectation values are calculated from the theoretical inversion potentials at finite temperatures. Key words: MO calculations, inversion potentials of thianthrene and thioxanthene; 1H NMR, thioxanthene; spin–spin coupling constants, long range, in thioxanthene.

Polarization consistent basis sets using the projector augmented wave method: a renovation brought by PAW into Gaussian basis sets

2020 ◽  
Vol 22 (46) ◽  
pp. 27037-27052
Author(s):  
Quan Manh Phung ◽  
Masaya Hagai ◽  
Xiao-Gen Xiong ◽  
Takeshi Yanai
Keyword(s):  
Dft Calculations ◽  
Basis Set ◽  
Basis Sets ◽  
Wave Method ◽  
Gaussian Basis Sets ◽  
New Family ◽  
Consistent Basis ◽  
Projector Augmented Wave

A new family of polarization consistent basis set, combined with the projector augmented wave method, was introduced. The basis sets are compact and have good performance as compared to conventional all-electron basis sets in DFT calculations.

The Effects of Split Valence Basis Sets on Muon Hyperfine Interaction in Guanine Nucleobase and Nucleotide Structures

2019 ◽  
Vol 966 ◽  
pp. 222-228 ◽  
Author(s):  
Wan Nurfadhilah Zaharim ◽  
Shukri Sulaiman ◽  
Siti Nuramira Abu Bakar ◽  
Nur Eliana Ismail ◽  
Harison Rozak ◽  
...  
Keyword(s):  
Total Energy ◽  
Hyperfine Interactions ◽  
Phosphate Group ◽  
Basis Set ◽  
Basis Sets ◽  
Cluster Method ◽  
Sugar Phosphate ◽  
Atomic Orbitals ◽  
Fermi Contact ◽  
Triple Zeta

The DFT cluster method was employed to investigate the electronic structures and muonium hyperfine interactions in guanine nucleobase and nucleotide using three different basis sets. The total energy and Fermi contact values were calculated for muon trapped at carbon '8'. The three basis sets, 6-31G, 6-311G and 6-311G(d,p), were used in tandem with the B3LYP functional. There are significant quantitative differences in the calculated total energy. 6-311G(d,p) produced the lowest total energy as compared to the other basis sets. The lowering of the total energy is due to the increase in the number of basis functions to describe the atomic orbitals, which is consistent with the postulate on basis set completeness. The 6-31G basis set produced the muon Fermi contact value that is the closest to the experimental value. The calculated Fermi contact values for the nucleobase and nucleotide are significantly lowered in going from the double-zeta to the triple-zeta basis set by 5% and 4% respectively. The lowering of the Fermi contact value can be attributed to the extension of the triple-zeta basis set in describing the valence atomic orbitals. The presence of the sugar phosphate group in the nucleotide instead of the methyl group tends to lower the Fermi contact value. Thus, the sugar phosphate group should be taken into consideration when designing a calculation model.

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