Linearized Coupled Cluster Corrections to Antisymmetrized Product of Strongly Orthogonal Geminals: Role of Dispersive Interactions

2013 ◽  
Vol 9 (6) ◽  
pp. 2602-2608 ◽  
Author(s):  
Tamás Zoboki ◽  
Ágnes Szabados ◽  
Péter R. Surján
Keyword(s):  
Coupled Cluster ◽  
Antisymmetrized Product

REDUCED MULTIREFERENCE COUPLED-CLUSTER METHOD AND ITS APPLICATION TO THE PYRIDYNE DIRADICALS

2008 ◽  
Vol 07 (04) ◽  
pp. 805-820 ◽  
Author(s):  
XIANGZHU LI ◽  
JOSEF PALDUS
Keyword(s):  
Molecular Geometry ◽  
External Source ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Triplet States ◽  
Correlation Effects ◽  
Spin Multiplicity ◽  
Triplet Splitting ◽  
Singlet And Triplet States

The reduced multireference (RMR) coupled-cluster (CC) method with singles and doubles (RMR CCSD) that employs a modest-size MR CISD wave function as an external source for the most important (primary) triples and quadruples in order to account for the nondynamic correlation effects in the presence of quasidegeneracy, and which is further perturbatively corrected for the remaining (secondary) triples, RMR CCSD(T), is employed to compute the molecular geometry and the energy of the lowest-lying singlet and triplet states, as well as the corresponding singlet–triplet splitting, for all possible isomers of the m, n-pyridyne diradicals. A comparison is made with earlier results that were obtained by other authors, and the role of the multireference effects for both the geometry and the spin multiplicity of the lowest state, as described by the RMR-type methods, is demonstrated on the example of 2,6- and 3,5-pyridynes.

Visible-light Photoresponse of Nitrogen-doped TiO2: Excited State Studies Using Time-dependent Density Functional Theory and Equation-of-Motion Coupled Cluster Methods

2010 ◽  
Vol 1263 ◽  
Author(s):  
Niranjan Govind ◽  
Roger Rousseau ◽  
Amity Andersen ◽  
Karol Kowalski
Keyword(s):  
Excited State ◽  
Density Functional ◽  
Equation Of Motion ◽  
Coupled Cluster ◽  
Functional Theory ◽  
Experimental Findings ◽  
High Level ◽  
Cluster Methods ◽  
Compare And Contrast

AbstractTo shed light on the nature of the electronic states at play in N-doped TiO2 nanoparticles, we have performed detailed ground and excited state calculations on pure and N-doped TiO2 rutile using an embedding model. We have validated our model by comparing ground-state embedded results with those obtained from periodic DFT calculations. Our results are consistent with periodic calculations. Using this embedding model we have performed B3LYP based TDDFT calculations of the excited state spectrum. We have also studied the lowest excitations using high-level equation-of-motion coupled cluster (EOMCC) approaches involving all single and inter-band double excitations. We compare and contrast the nature of the excitations in detail for the pure and doped systems using these calculations. Our calculations indicate a lowering of the bandgap and confirm the role of the N3- states on the UV/Vis spectrum of N-doped TiO2 rutile supported by experimental findings.

scholarly journals Role of electron correlation in the P,T -odd effects of CdH: A relativistic coupled-cluster investigation

2020 ◽  
Vol 101 (3) ◽  
Author(s):  
Kaushik Talukdar ◽  
Malaya K. Nayak ◽  
Nayana Vaval ◽  
Sourav Pal
Keyword(s):  
Electron Correlation ◽  
Coupled Cluster

Stationary coupled cluster response: Role of cubic terms in molecular properties

1994 ◽  
Vol 106 (2) ◽  
pp. 387-392
Author(s):  
Nayana Vaval ◽  
Keya Ghose ◽  
Priya Nair ◽  
Sourav Pal
Keyword(s):  
Molecular Properties ◽  
Coupled Cluster

TICC2 STATE-DEPENDENT CORRELATIONS IN NUCLEI

2003 ◽  
Vol 17 (28) ◽  
pp. 5203-5207 ◽  
Author(s):  
I. MOLINER
Keyword(s):  
Wave Function ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Coordinate Space ◽  
Coupled Cluster Method ◽  
State Dependent ◽  
Higher Order Terms ◽  
Finite Nuclei ◽  
Ground State Energies

We use the TICC2, a translationally invariant reformulation of the coupled cluster method (CCM) at the sub(2) level, to study finite nuclei within the p-shell. These nuclei were previously studied with the linearised TICI2 wave function, but the role of the higher order terms had not been discussed for nuclei. We shall include the quadratic terms of the wave function within a coordinate-space implementation of the method, and consider state-dependent correlations with the same structure as the semi-realistic interactions used. Using CCM techniques and gaussian expansions we compute the ground-state energies of these nuclei.

The role of the dihedral angle and excited cation states in ionization and dissociation of mono-halogenated biphenyls; a combined experimental and theoretical coupled cluster study

2019 ◽  
Vol 21 (8) ◽  
pp. 4556-4567 ◽  
Author(s):  
Michael Barclay ◽  
Ragnar Bjornsson ◽  
Maicol Cipriani ◽  
Andreas Terfort ◽  
D. Howard Fairbrother ◽  
...  
Keyword(s):  
Electron Impact ◽  
Dihedral Angle ◽  
Theoretical Investigation ◽  
Impact Ionization ◽  
Electron Impact Ionization ◽  
Coupled Cluster

State-selective fragmentation of halogenated biphenyls through electron impact ionization revealed through a joint experimental and theoretical investigation.

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