Configuration Interaction and Many‐Body Perturbation Theory: Application to Scandium,Titanium, and Iodine

A number of atoms and ions with complex valence configurations are considered as candidates for atomic clocks with high sensitivity to the possible variation of the fine‐structure constant. Present level of the theory is not sufficient to predict frequencies of the clock transitions with accuracy, required for the experiment. Here an approach is tested, where the second‐order perturbation theory is used to iteratively saturate configuration space for valence electrons. On the examples of scandium, titanium, and iodine, it is demonstrated that this improves the efficiency of the CI+MBPT method for systems with strong configuration interaction and/or more than three valence electrons.     

Information Criteria for the Degree of Turbulence Self-Organization

Turbulence is considered as a self-organizing process, and the information entropy serves as a criterion for the degree of its self-organization. The universal information criteria of the limiting degree of self-organization are determined for hierarchic systems. According to the Klimontovich S-theorem, the difference between the entropies of laminar and turbulent flows can be expressed through a function of the velocity pulsations whose stationary points correspond to the desired criteria. A comparison of the theoretical conclusions with the results of thermoanemometer measurements in air jets demonstrates their satisfactory agreement.