We introduce hybrid gausslet/Gaussian basis sets, where a standard Gaussian basis is added to a gausslet basis in order to increase accuracy near the nuclei while keeping the spacing of the grid of gausslets relatively large. The Gaussians are orthogonalized to the gausslets, which are already orthonormal, and approximations are introduced to maintain the diagonal property of the two electron part of the Hamiltonian, so that it continues to scale as the second power of the number of basis functions, rather than the fourth. We introduce several corrections to the Hamiltonian designed to enforce certain exact properties, such as the values of certain two-electron integrals. We also introduce a simple universal energy correction which compensates for the incompleteness of the basis stemming from the electron-electron cusps, based on the measured double occupancy of each basis function. We perform a number of Hartree Fock and full configuration interaction (full-CI) test calculations on two electron systems, and Hartree Fock on a ten-atom hydrogen chain, to benchmark these techniques. The inclusion of the cusp correction allows us to obtain complete basis set full-CI results, for the two electron cases, at the level of several microHartrees, and we see similar apparent accuracy for Hartree Fock on the ten-atom hydrogen chain.
Efficient time-dependent vibrational coupled cluster computations with time-dependent basis sets at the two-mode coupling level: full and hybrid TDMVCC[2]
Numerical local "hybrid" functional treatment of selected diatomic molecules: comparison of energies and multipole moments to conventional hybrid functionals
V. V. Karasiev在[J. Chem. Phys. { \bf 118}，8567（2003）]中提出的新的局部“混合”泛函以非局部混合泛函为基准。它们的性能测试的总和高占据轨道能量，以及选定的双原子分子的电矩。新的泛函，随着Hartree-Fock和非混合泛函，有限差分计算，这是独立的基础。计算了6- 311 G、6- 311 G ++G（3df，3 pd）和AUG-cc-pVnZ（n= 3，4，6）基组与Hartree-Fock和常规密度泛函方法结合时的总能量和电矩的基组误差。有限差分局部“杂交”和基组非局部杂交泛函的结果之间的比较表明，局部和非局部杂交泛函的总能量同意在基组误差。与基组误差相比，多极矩的离散性在幅度上较大，但仍然相当小（小于6- 311 G基组产生的误差）。因此，我们建议使用新的本地“混合”泛函时，精度预计是足够的，因为他们需要一个解决方案的只是微分科恩-沙姆方程，而不是积分微分的情况下的混合泛函。
Canonical and DLPNO-based G4(MP2)XK-inspired composite wavefunction methods parametrized against large and chemically diverse training sets: Are they more accurate and/or robust than double hybrid DFT?
Faster Exact Exchange for Solids via occ-RI-K: Application to Combinatorially Optimized Range-Separated Hybrid Functionals for Simple Solids with Pseudopotentials Near the Basis Set Limit
In this work, we developed and showcased the occ-RI-K algorithm to compute the exact exchange contribution in density functional calculations of solids near the basis set limit. Within the gaussian planewave (GPW) density fitting, our algorithm achieves a 1-2 orders of magnitude speedup compared to conventional GPW algorithms. Since our algorithm is well-suited for simulations with large basis sets, we applied it to 12 hybrid density functionals with pseudopotentials and a large uncontracted basis set to assess their performance on band gaps of 25 simple solids near the basis set limit. The la…
Assessment of Various Density Functionals and Basis Sets for the Calculation of Molecular Anharmonic Force Fields
In a previous contribution (Mol. Phys. { \bf 103}, xxxx, 2005), we established the suitability of density functional theory (DFT) for the calculation of molecular anharmonic force fields. In the present work, we have assessed a wide variety of basis sets and exchange-correlation functionals for harmonic and fundamental frequencies , equilibrium and ground-state rotational constants, and thermodynamic functions beyond the RRHO (rigid rotor-harmonic oscillator) approximation. The fairly good performance of double-zeta plus polarization basis sets for frequencies results from an error compensatio…
