Relativistic and correlated calculations on the ground and excited states of ThO.

We report on the performance of the third-order Douglas–Kroll ab initio model potential (DK3-AIMP) method-based electron-correlated spin–orbit calculations. Our treatment assumes that the problem can be separated into a spin–free correlation treatment and a spin–orbit calculation. The correlation effects were calculated using the multistate complete active space second-order perturbation method, and the spin–orbit effects were treated by means of the restricted active space state interaction spin–orbit method, where the spin–orbit effects were approximated by the Douglas–Kroll type of atomic mean-field spin–orbit method. We used our method for illustrative calculations on the ground and low-lying electronic states of thorium monoxide. For a proper description of the inner core region in the spin–orbit calculations, an auxiliary spin–orbit basis set was introduced. The DK3-AIMP-based electron-correlated spin–orbit calculations on ThO yield good agreement with corresponding all-electron results and with the available experimental data. This confirms that the DK3-AIMP method can be easily combined with highly accurate correlation treatments and relativistic effects, both of which are vital for studying the actinides. To our knowledge, the literature contains no references to AIMP calculations on the low-lying states of ThO. ©2003 American Institute of Physics

Dalende jeugdcriminaliteit

Juvenile crime declined hugely in the last ten years, not only in the Netherlands but in almost all western countries. This special issue focuses on cultural developments that potentially could explain the spectacular downward trend in juvenile crime. Various technological developments have changed the way young people spend leasure time and percept their environment . An example is the rise of smartphone use, as well as the popularity of social media and (online) computer games. Also attention is given to (indirect) effects of government policies on juvenile crime, such as the Dutch campaigns against alcohol consumption by juveniles and an educational law which mandates students to stay enrolled in school until age 18 (instead of 16) if they have not obtained at least a basic level of qualification (Startkwalificatie). Furthermore there are articles on the approach towards youth groups and on the Amsterdam Top600 Program aimed at those committing high-impact crimes.Read the introductory article by Bert Berghuis and Jaap de Waard in English: Declining juvenile crime – explanations for the international downtur

A theoretical study of the gas-phase chemiionization reactions La+O and La+O2

The La + O and La + O2 chemiionization reactions have been investigated with quantum chemical methods. For La + O2(X3?g) and La + O2(a1?g), the chemiionization reaction La + O2 ? LaO2+ + e? has been shown to be endothermic and does not contribute to the experimental chemielectron spectra. For the La + O2(X3?g) reaction conditions, chemielectrons are produced by La + O2 ? LaO + O, followed by La + O ? LaO+ + e?. This is supported by the same chemielectron band, arising from La + O ? LaO+ + e?, being observed from both the La + O(3P) and La + O2(X3?g) reaction conditions. For La + O2(a1?g), a chemielectron band with higher electron kinetic energy than that obtained from La + O2(X3?g) is observed. This is attributed to production of O(1D) from the reaction La + O2(a1?g) ? LaO + O(1D), followed by chemiionization via the reaction La + O(1D) ? LaO+ + e?. Potential energy curves are computed for a number of states of LaO, LaO* and LaO+ to establish mechanisms for the observed La + O ? LaO+ + e? chemiionization reactions