34 research outputs found
Impact-parameter dependence of K-shell ionisation in slow collisioons of near-symmetric relitivistic atoms
Abstract. The total K vacancy production probability of both collision partners in a heavy-ion-atom collision is calculated, assuming that two processes contribute, a single-collision process where 2po and 2pa vacancies are created by direct ionisation of the united atom and subsequently redistributed, and a double-collision process where a 2pa vacancy is created in the first collision and partially transferred in the second. The model used for the single-collision process is valid for slow collisions between partners of a combined charge greater than 70. Numerical results are presented for the (I, I) and (I, Ag) systems and show improved agreement with recent experiments. 1
Analysis of OPM potentials for multiplet states of 3d transition metal atoms
We apply the optimized effective potential method (OPM) to the multiplet
energies of the 3d transition metal atoms, where the orbital dependence of
the energy functional with respect to orbital wave function is the
single-configuration HF form. We find that the calculated OPM exchange
potential can be represented by the following two forms. Firstly, the
difference between OPM exchange potentials of the multiplet states can be
approximated by the linear combination of the potentials derived from the
Slater integrals and for the average
energy of the configuration. Secondly, the OPM exchange potential can be
expressed as the linear combination of the OPM exchange potentials of the
single determinants.Comment: 15 pages, 6 figures, to be published in J. Phys.
Parameterized optimized effective potential for atoms
The optimized effective potential equations for atoms have been solved by
parameterizing the potential. The expansion is tailored to fulfill the known
asymptotic behavior of the effective potential at both short and long
distances. Both single configuration and multi configuration trial wave
functions are implemented. Applications to several atomic systems are presented
improving previous works. The results here obtained are very close to those
calculated in either the Hartree-Fock and the multi configurational
Hartree-Fock framework.Comment: 8 pages, 3 figure
Lamb shifts and hyperfine structure in 6Li+ and 7Li+: Theory and experiment
High-precision laser-resonance measurements accurate to ±0.5 MHz or better are reported for transitions among the 1s2s 3S1-1s2p 3PJ hyperfine manifolds for each of J=0, 1, and 2 in both Li+6 and Li+7. A detailed analysis of hyperfine structure is performed for both the S and P states, using newly calculated values for the magnetic dipole and electric quadrupole coupling constants, and the hyperfine shifts subtracted from the measurements. The resulting transition frequencies are then analyzed on three different levels. First, the isotope shifts in the fine-structure splittings are calculated from the relativistic reduced mass and recoil terms in the Breit interaction, and compared with experiment at the ±0.5-MHz level of accuracy. This comparison is particularly significant because J-independent theoretical uncertainties reduce through cancellation to the ±0.01-MHz level. Second, the isotope shifts in the full transition frequencies are used to deduce the difference in rms nuclear radii. The result is Rrms(6Li)-Rrms(7Li)=0.15±0.01 fm, in agreement with nuclear scattering data, but with substantially improved accuracy. Third, high-precision calculations of the low-order non-QED contributions to the transition frequencies are subtracted from the measurements to obtain the residual QED shifts. The isotope-averaged and spin-averaged effective shift for Li+7 is 37 429.40±0.39 MHz, with an additional uncertainty of ±1.5 MHz due to finite nuclear size corrections. The accuracy of 11 parts per million is the best two-electron Lamb shift measurement in the literature, and is comparable to the accuracies achieved in hydrogen. Theoretical contributions to the two-electron Lamb shift are discussed, including terms of order (αZ)4 recently obtained by Chen, Cheng, and Johnson [Phys. Rev. A 47, 3692 (1993)], and the results used to extract a QED shift for the 2 3S1 state. The result of 30 254±12 MHz is shown to be in good accord with theory (30 250±30 MHz) when two-electron corrections to the Bethe logarithm are taken into account by a 1/Z expansion method. © 1994 The American Physical Society
Inspekcje kamerami IP CCTV w wiertnictwie
The introduction of IP CCTV cameras has made it technically possible to have remote surveillance and control of drilling equipment. The live video transmission on Internet (or UMTS/GSM) enables integrated drilling operations from a drilling control room situated at the drilling company headquarter. Using Internet (or even UMTS/ GSM) this integrated operation drilling control room can give support to a number of drilling operations at different locations. As an example, the presentation will give a brief description of an integrated operation drilling control room giving support to a number of drilling rigs in the North Sea. The presentation will focus on the IP CCTV part, but will also cover the real time data and control transfer of data from the drilling rig to the integrated operation control room.Wprowadzenie analogowych kamer o wysokiej rozdzielczości umożliwiło prowadzenie obserwacji sprzętu wiertniczego. Internetowe transmisje wideo "na żywo" (lub UMTS/GSM) umożliwiają sterowanie zintegrowanych prac wiertniczych z punktu sterowania. Za pomocą internetu (lub UMTS/GSM) w punkcie sterowania realizowane jest wspomaganie działań wiertniczych w różnych miejscach. W artykule przedstawiono przykładowy ogólny opis punktu sterowania zintegrowanymi pracami wiertniczymi, wspomagającego pracę wielu wiertni na Morzu Północnym. W artykule skupiono uwagę na analogowych kamerach o wysokiej rozdzielczości IP CCTV, jak również danych czasu rzeczywistego oraz sterowaniem przekazem danych z wiertni do punktu sterowania
Impact parameter dependence of K-shell ionisation in slow collisions of near-symmetric relativistic atoms
Abstract. The total K vacancy production probability of both collision partners in a heavy-ion-atom collision is calculated, assuming that two processes contribute, a single-collision process where 2po and 2pa vacancies are created by direct ionisation of the united atom and subsequently redistributed, and a double-collision process where a 2pa vacancy is created in the first collision and partially transferred in the second. The model used for the single-collision process is valid for slow collisions between partners of a combined charge greater than 70. Numerical results are presented for the (I, I) and (I, Ag) systems and show improved agreement with recent experiments. 1