Affecting Factors of Public Employees’ Ganizational Commitment

Purpose – The aim of this chapter is to shed some light on the antecedents of organizational commitment, the mediating role of job engagement and job satisfaction as determinants of organizational commitment within the public sector environment, and the effects that national cultural values may have on these relationships. Approach – This paper presents a review of the works that, from both theoretical and empirical points of view, explore the affecting factors of public employees’ organizational commitment in an international setting. Findings – A comprehensive model has been developed, detailing the expectations on the influence that these factors might have on public employees’ level of commitment, either as mediators or moderators. Research limitations/implications – The main limitation is the paper’s theoretical nature; the subsequent implication is a future empirical research that may prove or disprove these theoretical findings. In addition, there are some other possible mediating factors and antecedents which may be of interest for future researchers. Originality/value – This comprehensive review of the extant literature may provide academics and public managers with a deeper comprehension of how organizational commitment might be achieved, and why some practices may or may not be transferrable from one country to another.

Can model Hamiltonians describe the electron–electron interaction in π-conjugated systems?: PAH and graphene

Model Hamiltonians have been, and still are, a valuable tool for investigating the electronic structure of systems for which mean field theories work poorly. This review will concentrate on the application of Pariser–Parr–Pople (PPP) and Hubbard Hamiltonians to investigate some relevant properties of polycyclic aromatic hydrocarbons (PAH) and graphene. When presenting these two Hamiltonians we will resort to second quantisation which, although not the way chosen in its original proposal of the former, is much clearer. We will not attempt to be comprehensive, but rather our objective will be to try to provide the reader with information on what kinds of problems they will encounter and what tools they will need to solve them. One of the key issues concerning model Hamiltonians that will be treated in detail is the choice of model parameters. Although model Hamiltonians reduce the complexity of the original Hamiltonian, they cannot be solved in most cases exactly. So, we shall first consider the Hartree–Fock approximation, still the only tool for handling large systems, besides density functional theory (DFT) approaches. We proceed by discussing to what extent one may exactly solve model Hamiltonians and the Lanczos approach. We shall describe the configuration interaction (CI) method, a common technology in quantum chemistry but one rarely used to solve model Hamiltonians. In particular, we propose a variant of the Lanczos method, inspired by CI, that has the novelty of using as the seed of the Lanczos process a mean field (Hartree–Fock) determinant (the method will be named LCI). Two questions of interest related to model Hamiltonians will be discussed: (i) when including long-range interactions, how crucial is including in the Hamiltonian the electronic charge that compensates ion charges? (ii) Is it possible to reduce a Hamiltonian incorporating Coulomb interactions (PPP) to an 'effective' Hamiltonian including only on-site interactions (Hubbard)? The performance of CI will be checked on small molecules. The electronic structure of azulene and fused azulene will be used to illustrate several aspects of the method. As regards graphene, several questions will be considered: (i) paramagnetic versus antiferromagnetic solutions, (ii) forbidden gap versus dot size, (iii) graphene nano-ribbons, and (iv) optical properties.