Electromagnetic transitions of the helium atom in superstrong magnetic fields

We investigate the electromagnetic transition probabilities for the helium atom embedded in a superstrong magnetic field taking into account the finite nuclear mass. We address the regime \gamma=100-10000 a.u. studying several excited states for each symmetry, i.e. for the magnetic quantum numbers 0,-1,-2,-3, positive and negative z parity and singlet and triplet symmetry. The oscillator strengths as a function of the magnetic field, and in particular the influence of the finite nuclear mass on the oscillator strengths are shown and analyzed.Comment: 10 pages, 8 figure

Helium in superstrong magnetic fields

We investigate the helium atom embedded in a superstrong magnetic field gamma=100-10000 au. All effects due to the finite nuclear mass for vanishing pseudomomentum are taken into account. The influence and the magnitude of the different finite mass effects are analyzed and discussed. Within our full configuration interaction approach calculations are performed for the magnetic quantum numbers M=0,-1,-2,-3, singlet and triplet states, as well as positive and negative z parities. Up to six excited states for each symmetry are studied. With increasing field strength the number of bound states decreases rapidly and we remain with a comparatively small number of bound states for gamma=10^4 au within the symmetries investigated here.Comment: 16 pages, including 14 eps figures, submitted to Phys. Rev.

Climate change response: a report to establish the knowledge required for a TIANZ response and policy formulation with the Government post Kyoto Protocol ratification

The Tourism Industry Association of New Zealand commissioned this report ‘as a definitive reference point for the Tourism sector with regard to its greenhouse gas emissions (CO₂) and the potential impacts on the sector, in order to establish the underpinning knowledge required for a subsequent TIANZ response and policy formulation with the Government post the Kyoto Protocol ratification’. The value of the tourism sector, in terms of GDP and employment is self-evident but there is also growing awareness of the New Zealand environment by the international market which is critical to New Zealand’s future prosperity. Both the tourism sector and the Government recognise the importance of the ‘state of New Zealand’s environment’ and the need to genuinely sustain the image of ‘100% Pure New Zealand’, as it is implicitly linked to maintaining credibility and growth in a highly competitive market.Prepared for the Tourism Industry Association New Zealand (TIANZ), Landcare Research Contract Report, LC0102/107

The helium atom in a strong magnetic field

We investigate the electronic structure of the helium atom in a magnetic field b etween B=0 and B=100a.u. The atom is treated as a nonrelativistic system with two interactin g electrons and a fixed nucleus. Scaling laws are provided connecting the fixed-nucleus Hamiltonia n to the one for the case of finite nuclear mass. Respecting the symmetries of the electronic Ham iltonian in the presence of a magnetic field, we represent this Hamiltonian as a matrix with res pect to a two-particle basis composed of one-particle states of a Gaussian basis set. The corresponding generalized eigenvalue problem is solved numerically, providing in the present paper results for vanish ing magnetic quantum number M=0 and even or odd z-parity, each for both singlet and triplet spin symmetry. Total electronic energies of the ground state and the first few excitations in each su bspace as well as their one-electron ionization energies are presented as a function of the magnetic fie ld, and their behaviour is discussed. Energy values for electromagnetic transitions within the M=0 sub space are shown, and a complete table of wavelengths at all the detected stationary points with respect to their field dependence is given, thereby providing a basis for a comparison with observed ab sorption spectra of magnetic white dwarfs.Comment: 21 pages, 4 Figures, acc.f.publ.in J.Phys.

Annual Reports

This segment includes the annual reports of the President, Executive Director, and staff of the Newport Historical Society. These reports detail the progress made during this very productive year in carrying out the Society\u27s mission to collect and preserve the artifacts of Newport County\u27s history

Exchange and correlation energies of ground states of atoms and molecules in strong magnetic fields

Using a Hartree-Fock mesh method and a configuration interaction approach based on a generalized Gaussian basis set we investigate the behaviour of the exchange and correlation energies of small atoms and molecules, namely th e helium and lithium atom as well as the hydrogen molecule, in the presence of a magnetic field covering the regime B=0-100a.u. In general the importance of the exchange energy to the binding properties of at oms or molecules increases strongly with increasing field strength. This is due to the spin-flip transitions and in particular due to the contributions of the tightly bound hydrogenic state s which are involved in the corresponding ground states of different symmetries. In contrast to the exchange energy the correlation energy becomes less relevant with increasing field strength. This holds for the individual configurations constituting the ground state and for the crossovers of the global ground state.Comment: 4 Figures acc.f.publ.in Phys.Rev.

The ground state of the carbon atom in strong magnetic fields

The ground and a few excited states of the carbon atom in external uniform magnetic fields are calculated by means of our 2D mesh Hartree-Fock method for field strengths ranging from zero up to 2.35 10^9 T. With increasing field strength the ground state undergoes six transitions involving seven different electronic configurations which belong to three groups with different spin projections S_z=-1,-2,-3. For weak fields the ground state configuration arises from the field-free 1s^2 2s^2 2p_0 2p_{-1}, S_z=-1 configuration. With increasing field strength the ground state involves the four S_z=-2 configurations 1s^22s2p_0 2p_{-1}2p_{+1}, 1s^22s2p_0 2p_{-1}3d_{-2}, 1s^22p_0 2p_{-1}3d_{-2}4f_{-3} and 1s^22p_{-1}3d_{-2}4f_{-3}5g_{-4}, followed by the two fully spin polarized S_z=-3 configurations 1s2p_02p_{-1}3d_{-2}4f_{-3}5g_{-4} and 1s2p_{-1}3d_{-2}4f_{-3}5g_{-4}6h_{-5}. The last configuration forms the ground state of the carbon atom in the high field regime \gamma>18.664. The above series of ground state configurations is extracted from the results of numerical calculations for more than twenty electronic configurations selected due to some general energetical arguments.Comment: 6 figures,acc. Phys.Rev.

The HeH+HeH^+ molecular ion in a magnetic field

A detailed study of the low-lying electronic states {}^1\Si,{}^3\Si,{}^3\Pi,{}^3\De of the $\rm{HeH}^+$ molecular ion in parallel to a magnetic field configuration (when \al-particle and proton are situated on the same magnetic line) is carried out for $B=0-4.414\times 10^{13}$ G in the Born-Oppenheimer approximation. The variational method is employed using a physically adequate trial function. It is shown that the parallel configuration is stable with respect to small deviations for \Si-states. The quantum numbers of the ground state depend on the magnetic field strength. The ground state evolves from the spin-singlet {}^1\Si state for small magnetic fields $B\lesssim 0.5$ a.u. to the spin-triplet {}^3\Si unbound state for intermediate fields and to the spin-triplet strongly bound $^3\Pi$ state for $B \gtrsim 15$ a.u. When the $\rm{HeH}^+$ molecular ion exists, it is stable with respect to a dissociation.Comment: 13 pages, 5 figures, 4 table