First principles calculation of vibrational Raman spectra in large systems: signature of small rings in crystalline SiO2

We present an approach for the efficient calculation of vibrational Raman intensities in periodic systems within density functional theory. The Raman intensities are computed from the second order derivative of the electronic density matrix with respect to a uniform electric field. In contrast to previous approaches, the computational effort required by our method for the evaluation of the intensities is negligible compared to that required for the calculation of vibrational frequencies. As a first application, we study the signature of 3- and 4-membered rings in the the Raman spectra of several polymorphs of SiO2, including a zeolite having 102 atoms per unit cell.Comment: 4 pages, 2 figures, revtex4 Minor corrections; accepted in Phys. Rev. Let

Differences in personality and the sharing of managerial tacit knowledge: an empirical analysis of public sector managers in Malaysia

Purpose – This study aims to identify differences in knowledge-sharing mechanisms and personality among expert, typical and novice managers within the Malaysian public sector. Strengthening knowledge sharing function is essential for enabling public institutions around the world to be more productive. Design/methodology/approach – This quantitative study involves 308 employees from management and professional groups within 98 local authorities in the Malaysian local government. Stratified random sampling techniques were used and the sampling frame comprised 1,000 staff using postal surveys. Data analyses were carried out using analysis of variance and correlations to test the research hypotheses. Findings – The findings reveal that expert managers are more proactive in sharing their knowledge, particularly those with the personality traits of conscientiousness and openness. These two personality traits were also related to expert behaviours such as thoroughness, responsibility and persistence, which led to work competency and managerial success. Originality/value – This study provides theoretical insights into how managerial tacit knowledge differs and can accumulate, depending on the personality traits of middle managers. The paper shows the different mechanisms of knowledge sharing, tacit knowledge and personality among expert, typical and novice managers. Practically, this study is important for guiding senior managers in their attempts to identify the most appropriate personalities of their middle managers. This study found that the expert group was higher in conscientiousness, openness and overall personality traits compared with the typical and novice groups. The paper also highlights the value of sharing managerial tacit knowledge effectively