scholarly journals Improved Spin-State Energy Differences of Fe(II) Molecular and Crystalline Complexes via the Hubbard U-Corrected Density

2021 ◽  
Author(s):  
Lorenzo A. Mariano ◽  
Bess Vlaisavljevich ◽  
Roberta Poloni
Keyword(s):  
Spin State ◽  
State Energy ◽  
Hubbard U

Theoretical Study on the Spin-State Energy Splittings and Local Spin in Cationic [Re]−Cn−[Re] Complexes

2005 ◽  
Vol 44 (18) ◽  
pp. 6174-6182 ◽  
Author(s):  
Carmen Herrmann ◽  
Johannes Neugebauer ◽  
John A. Gladysz ◽  
Markus Reiher
Keyword(s):  
Spin State ◽  
State Energy ◽  
Theoretical Study ◽  
Local Spin

Accurate calculation of spin-state energy gaps in Fe(III) Spin-Crossover systems using Density Functional Methods

2021 ◽  
Author(s):  
Daniel Vidal ◽  
Jordi Ribas-Ariño ◽  
Jordi Cirera
Keyword(s):  
Spin State ◽  
Density Functional ◽  
Spin Crossover ◽  
State Energy ◽  
Accurate Calculation ◽  
Density Functional Methods ◽  
Functional Methods ◽  
Energy Gaps

Fe(III) complexes are receiving ever-increasing attention as spin crossover (SCO) systems because they are usually air stable, as opposed to Fe(II) complexes, which are prone to oxidation. Here, we present...

scholarly journals Localized Active Space Pair-Density Functional Theory

2021 ◽  
Author(s):  
Riddhish Pandharkar ◽  
Matthew R. Hermes ◽  
Christopher J. Cramer ◽  
Donald G. Truhlar ◽  
Laura Gagliardi
Keyword(s):  
Density Functional Theory ◽  
Wave Function ◽  
Spin State ◽  
Density Functional ◽  
State Energy ◽  
Correlation Energy ◽  
Functional Theory ◽  
Active Space ◽  
Energy Gaps ◽  
Pair Density

Accurate quantum chemical methods for the prediction of spin-state energy gaps for strongly correlated systems are computationally expensive and scale poorly with the size of the system. This makes calculations for many experimentally interesting molecules impractical even with abundant computational resources. In previous work, we have shown that the localized active space (LAS) self-consistent field (SCF) method is an efficient way to obtain multi-configuration SCF wave functions of comparable quality to the corresponding complete active space (CAS) ones. To obtain quantitative results, a post-SCF method is needed to estimate the complete correlation energy. One such method is multiconfiguration pair-density functional theory (PDFT), which calculates the energy based on the density and on-top pair density obtained from a multiconfiguration wave function. In this work we introduce localized-active-space pair-density functional theory, which uses a LAS wave function for subsequent PDFT calculations. The method is tested for computing spin-state energy gaps in conjugated organic molecules and bimetallic compounds and is shown to give results within 0.05 eV of the corresponding CAS-PDFT results at a significantly lower cost.

scholarly journals Localized Active Space Pair-Density Functional Theory

2021 ◽  
Author(s):  
Riddhish Pandharkar ◽  
Matthew R. Hermes ◽  
Christopher J. Cramer ◽  
Donald G. Truhlar ◽  
Laura Gagliardi
Keyword(s):  
Density Functional Theory ◽  
Wave Function ◽  
Spin State ◽  
Density Functional ◽  
State Energy ◽  
Correlation Energy ◽  
Functional Theory ◽  
Active Space ◽  
Energy Gaps ◽  
Pair Density

Accurate quantum chemical methods for the prediction of spin-state energy gaps for strongly correlated systems are computationally expensive and scale poorly with the size of the system. This makes calculations for many experimentally interesting molecules impractical even with abundant computational resources. In previous work, we have shown that the localized active space (LAS) self-consistent field (SCF) method is an efficient way to obtain multi-configuration SCF wave functions of comparable quality to the corresponding complete active space (CAS) ones. To obtain quantitative results, a post-SCF method is needed to estimate the complete correlation energy. One such method is multiconfiguration pair-density functional theory (PDFT), which calculates the energy based on the density and on-top pair density obtained from a multiconfiguration wave function. In this work we introduce localized-active-space pair-density functional theory, which uses a LAS wave function for subsequent PDFT calculations. The method is tested for computing spin-state energy gaps in conjugated organic molecules and bimetallic compounds and is shown to give results within 0.05 eV of the corresponding CAS-PDFT results at a significantly lower cost.

The angular dependence of spin-state energy splittings in the core

2013 ◽  
Vol 111 (9-11) ◽  
pp. 1482-1491 ◽  
Author(s):  
Lynn Groß ◽  
Torben Steenbock ◽  
Carmen Herrmann
Keyword(s):  
Angular Dependence ◽  
Spin State ◽  
State Energy ◽  
The Core

Electron energy-loss near-edge structure in silicate minerals

1992 ◽  
Vol 50 (2) ◽  
pp. 1258-1259
Author(s):  
D W McComb ◽  
R S Payne ◽  
P L Hansen ◽  
R Brydson
Keyword(s):  
Solid State ◽  
Energy Loss ◽  
Electron Energy ◽  
State Energy ◽  
Local Environment ◽  
Edge Structure ◽  
Silicate Minerals ◽  
Two Samples ◽  
Electron Energy Loss ◽  
Careful Processing

Electron energy-loss near-edge structure (ELNES) is an effective probe of the local geometrical and electronic environment around particular atomic species in the solid state. Energy-loss spectra from several silicate minerals were mostly acquired using a VG HB501 STEM fitted with a parallel detector. Typically a collection angle of ≈8mrad was used, and an energy resolution of ≈0.5eV was achieved.Other authors have indicated that the ELNES of the Si L2,3-edge in α-quartz is dominated by the local environment of the silicon atom i.e. the SiO4 tetrahedron. On this basis, and from results on other minerals, the concept of a coordination fingerprint for certain atoms in minerals has been proposed. The concept is useful in some cases, illustrated here using results from a study of the Al2SiO5 polymorphs (Fig.l). The Al L2,3-edge of kyanite, which contains only 6-coordinate Al, is easily distinguished from andalusite (5- & 6-coordinate Al) and sillimanite (4- & 6-coordinate Al). At the Al K-edge even the latter two samples exhibit differences; with careful processing, the fingerprint for 4-, 5- and 6-coordinate aluminium may be obtained.

Associations Between Self-Report of Emotional State and the EEG Patterns in Affective Disorders Patients

2010 ◽  
Vol 24 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Miroslaw Wyczesany ◽  
Jan Kaiser ◽  
Anton M. L. Coenen
Keyword(s):  
State Energy ◽  
Emotional State ◽  
Spectral Power ◽  
Bipolar Affective Disorder ◽  
Affective State ◽  
Manic Episode ◽  
High Energy ◽  
Self Report ◽  
Major Depressive ◽  
High Tension

The study determines the associations between self-report of ongoing emotional state and EEG patterns. A group of 31 hospitalized patients were enrolled with three types of diagnosis: major depressive disorder, manic episode of bipolar affective disorder, and nonaffective patients. The Thayer ADACL checklist, which yields two subjective dimensions, was used for the assessment of affective state: Energy Tiredness (ET) and Tension Calmness (TC). Quantitative analysis of EEG was based on EEG spectral power and laterality coefficient (LC). Only the ET scale showed relationships with the laterality coefficient. The high-energy group showed right shift of activity in frontocentral and posterior areas visible in alpha and beta range, respectively. No effect of ET estimation on prefrontal asymmetry was observed. For the TC scale, an estimation of high tension was related to right prefrontal dominance and right posterior activation in beta1 band. Also, decrease of alpha2 power together with increase of beta2 power was observed over the entire scalp.

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