14 research outputs found
New Strategies in Modeling Electronic Structures and Properties with Applications to Actinides
This chapter discusses contemporary quantum chemical methods and provides
general insights into modern electronic structure theory with a focus on
heavy-element-containing compounds. We first give a short overview of
relativistic Hamiltonians that are frequently applied to account for
relativistic effects. Then, we scrutinize various quantum chemistry methods
that approximate the -electron wave function. In this respect, we will
review the most popular single- and multi-reference approaches that have been
developed to model the multi-reference nature of heavy element compounds and
their ground- and excited-state electronic structures. Specifically, we
introduce various flavors of post-Hartree--Fock methods and optimization
schemes like the complete active space self-consistent field method, the
configuration interaction approach, the Fock-space coupled cluster model, the
pair-coupled cluster doubles ansatz, also known as the antisymmetric product of
1 reference orbital geminal, and the density matrix renormalization group
algorithm. Furthermore, we will illustrate how concepts of quantum information
theory provide us with a qualitative understanding of complex electronic
structures using the picture of interacting orbitals. While modern quantum
chemistry facilitates a quantitative description of atoms and molecules as well
as their properties, concepts of quantum information theory offer new
strategies for a qualitative interpretation that can shed new light onto the
chemistry of complex molecular compounds.Comment: 43 pages, 3 figures, Version of Recor
Comparação do equilĂbrio dinâmico entre praticantes de Brazilian Jiu-Jitsu com diferentes nĂveis de experiĂŞncia
Resumo O objetivo do presente estudo foi analisar o equilĂbrio dinâmico em praticantes experientes e iniciantes de Brazilian Jiu-Jitsu (BJJ) e grupo controle. A amostra do presente estudo foi composta por 34 participantes, com idades entre 20 e 42 anos, divididos em trĂŞs grupos: 10 praticantes de BJJ Experientes, 12 praticantes de BJJ Iniciantes e 12 nĂŁo praticantes de BJJ que compuseram o grupo controle. A tarefa do protocolo consistiu na busca do equilĂbrio sobre um estabilĂ´metro, com o objetivo de manter a plataforma o mais perto possĂvel da posição horizontal (ângulo de 0 a 3Âş de desvio máximo) durante cada tentativa de 90 segundos. Os resultados demonstram diferenças significativas entre os grupos [F(2,31) = 30,24; p < 0,001]. AtravĂ©s dos testes de "post-hoc" foram detectadas diferenças entre o grupo Experientes (46 ± 14 s) e os outros dois grupos, Iniciantes (25 ± 6 s, p < 0,001) e Grupo Controle (19 ± 4 s, p < 0,001). Todavia, nĂŁo foram encontradas diferenças significativas entre os Grupo Controle e Iniciantes (p = 0,421). Os resultados sugerem que o tempo de prática de BJJ pode influenciar no desempenho do controle do equilĂbrio