Self-consistent molecular orbital methods. XX. A basis set for correlated wave functions

Krishnan, R.; Binkley, J. Stephen; Seeger, Rolf; Pople, John A.

doi:10.1063/1.438955

Cited by 15,732 publications

(9,201 citation statements)

References 9 publications

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“…The electronic structure was described using density functional theory (DFT) for the electronic ground state and time-dependent density functional theory (TDDFT) for the excited states. Due to the Rydberg character of the low-lying electronically excited states of adamantane, the long-range-corrected CAM-B3LYP functional 40 combined with the 6-311++G** basis set 41 containing diffuse basis functions was employed. This ensures an accurate description of these states, as is evident from the very good agreement between the theoretical and experimental spectra.…”

Section: Methodsmentioning

confidence: 99%

Size and shape dependent photoluminescence and excited state decay rates of diamondoids

Richter

Wolter

Zimmermann

et al. 2014

Phys. Chem. Chem. Phys.

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We present photoluminescence spectra and excited state decay rates of a series of diamondoids, which represent molecular structural analogues to hydrogen-passivated bulk diamond. Specific isomers of the five smallest diamondoids (adamantane-pentamantane) have been brought into the gas phase and irradiated with synchrotron radiation. All investigated compounds show intrinsic photoluminescence in the ultraviolet spectral region. The emission spectra exhibit pronounced vibrational fine structure which is analyzed using quantum chemical calculations. We show that the geometrical relaxation of the first excited state of adamantane, exhibiting Rydberg character, leads to the loss of T d symmetry. The luminescence of adamantane is attributed to a transition from the delocalized first excited state into different vibrational modes of the electronic ground state. Similar geometrical changes of the excited state structure have also been identified in the other investigated diamondoids. The excited state decay rates show a clear dependence on the size of the diamondoid, but are independent of the particle geometry, further indicating a loss of particle symmetry upon electronic excitation.

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Section: Methodsmentioning

confidence: 99%

Size and shape dependent photoluminescence and excited state decay rates of diamondoids

Richter

Wolter

Zimmermann

et al. 2014

Phys. Chem. Chem. Phys.

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“…For Ce as well as for La we have applied (6s5p4d)/[4s3p2d] valence basis sets [14]. For the nitrogen atoms, the standard 6-311G* Gaussian function basis set was used without any modification [15]. The integral tolerances were employed to compute the infinite Coulomb and HF exchange series: 10 −7 for the Coulomb For evaluating cohesive energies, we subtracted the ground-state energies of the free atom.…”

Section: Resultsmentioning

confidence: 99%

Cohesive properties of CeN and LaN from first principles

Voloshina

Paulus

2008

J Comput Chem

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The electron-correlation effects on the ground-state properties of CeN and LaN are studied by ab initio quantum-chemical methods. The approach which is used consists in the combination of two separate steps: 1) the ground-state Hartree-Fock calculations for the crystal; 2) application of the method of increments to the studied system, which allows an expansion of bulk properties using the information from quantum-chemical calculations performed for finite cluster. As it can be expected, for CeN correlation plays a significant role: with Hartree-Fock method only 49 % of the experimental cohesive energy has been covered, whereas after correlation corrections (coupled-cluster approach) the ground-state properties were found to be in good agreement with the experimental data found in literature. Thus, we obtained about 90 % of the expected cohesive energy; the computed lattice constants and bulk moduli agree also well with the experimental values. For comparison the equivalent treatment has been performed for LaN, where no f orbital is occupied. There the HF contribution to the ground-state properties is larger and hence the correlation effects weaker.

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“…Model (CPCM) [35][36][37][38][39] in conjunction with the united atom (UA) cavity-model in-tagged with Kohn-Sham (KS) radii (UAKS) [40][41] with water as a solvent ( = 78.39). We performed frequency calculations by determining analytically the second derivatives of the UB3LYP potential energy surfaces with respect to the fixed atomic nuclear coordinates to determine whether each of the minimized structures corresponded to an energy minimum or a saddle point.…”

Section: Methodsmentioning

confidence: 99%

A Density Functional Theory- and Atoms in Molecules-based Study of NiNTA and NiNTPA Complexes toward Physical Properties Controlling their Stability. A New Method of Computing a Formation Constant

Cukrowski

Govender

2010

Inorg. Chem.

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The log K 1 value of analytical quality was obtained for the NiNTPA complex using the DFTcomputed (at the B3LYP/6-311++G(d,p) level of theory in solvent, CPCM/UAKS) G (aq) values of the lowest energy conformers of the ligands, NTA (nitrilotriacetic acid) and NTPA (nitrilotri-3-propanoic acid), and Ni(II) complexes (NiNTA and NiNTPA). The described mathematical protocol is of general nature. The topological analysis, based on the Quantum Theory of Atoms in Molecules (QTAIM) of Bader, was used to characterize coordination bonds, chelating rings and additional intramolecular interactions in the complexes. The topological data, but not the structural analysis, explained the observed difference in stability of the NiNTA and NiNTPA complexes. It was found that the structural H···H contacts (classically regarded H-clashes, a steric hindrance destabilizing the complex) are in fact the H-H bonds contributing to the overall stability of NiNTPA. Also a CH-O bond was found in NiNTPA. The absence of intramolecular bonds between the atoms that fulfill a distance criterion in NiNTPA is explained by the formation of adjacent intramolecular rings that have larger electron density at the ring critical points when compared with the rings containing these atoms. It is postulated that the strength of a chelating ring (a chelating effect) can be measured by the electron density at the ring critical point. It was found that the strain energy, E s , in the as-in-complex NTPA ligand (E s is significantly lowered by the presence of the intramolecular bonded interactions found by QTAIM) is responsible for the decrease in strength of NiNTPA; the E s ratio (NTPA/NTA) of 1.9 correlates well with the experimental log K 1 ratio (NTA/NTPA) of 1.98.2

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Self-consistent molecular orbital methods. XX. A basis set for correlated wave functions

Cited by 15,732 publications

References 9 publications

Size and shape dependent photoluminescence and excited state decay rates of diamondoids

Size and shape dependent photoluminescence and excited state decay rates of diamondoids

Cohesive properties of CeN and LaN from first principles

A Density Functional Theory- and Atoms in Molecules-based Study of NiNTA and NiNTPA Complexes toward Physical Properties Controlling their Stability. A New Method of Computing a Formation Constant

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