arXiv subjects

M. V. Ivanov

Publications and source records attributed to M. V. Ivanov.

42 records · Page 3Linked to original sources

arXiv2000

The beryllium atom and beryllium positive ion in strong magnetic fields

The ground and a few excited states of the beryllium 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*10^9T. With changing field strength the ground state of the Be atom undergoes three transitions involving four different electronic configurations which belong to three groups with different spin projections S_z=0,-1,-2. For weak fields the ground state configuration arises from the 1s^2 2s^2, S_z=0 configuration. With increasing field strength the ground state evolves into the two S_z=-1 configurations 1s^22s 2p_{-1} and 1s^2 2p_{-1}3d_{-2}, followed by the fully spin polarised S_z=-2 configuration 1s2p_{-1}3d_{-2}4f_{-3}. The latter configuration forms the ground state of the beryllium atom in the high field regime γ>4.567. The analogous calculations for the Be^+ ion provide the sequence of the three following ground state configurations: 1s^22s and 1s^22p_{-1} (S_z=-1/2) and 1s2p_{-1}3d_{-2} (S_z=-3/2).

physics.atom-ph↗

arXiv2000

Generator Coordinate Method Calculations for Ground and First Excited Collective States in $^{4}$He, $^{16}$O and $^{40}$Ca Nuclei

The main characteristics of the ground and, in particular, the first excited monopole state in the $^{4}$He, $^{16}$O and $^{40}$Ca nuclei are studied within the generator coordinate method using Skyrme-type effective forces and three construction potentials, namely the harmonic-oscillator, the square-well and Woods-Saxon potentials. Calculations of density distributions, radii, nucleon momentum distributions, natural orbitals, occupation numbers and depletions of the Fermi sea, as well as of pair density and momentum distributions are carried out. A comparison of these quantities for both ground and first excited monopole states with the available empirical data and with the results of other theoretical methods are given and discussed in detail.

nucl-th↗

arXiv1999

Ground states of the atoms H, He,...., Ne and their singly positive ions in strong magnetic fields: The high field regime

The electronic structure of the ground and some excited states of neutral atoms with the nuclear charge numbers $1\leq Z \leq 10$ and their single positive ions are investigated by means of our 2D mesh Hartree-Fock method for strong magnetic fields $0.5\leq γ\leq 10000$. For $γ=10000$ the ground state configurations of all the atoms and ions considered are given by fully spin-polarized configurations of single-electron orbitals with magnetic quantum numbers ranging from m=0 to m=-N+1 where N is the number of the electrons. Focusing on the fully spin polarized situation we provide critical values of the magnetic field strength for which crossovers with respect to the spatial symmetries of the ground state take place. It is found that the neutral atoms and singly charged positive ions with $2\leq Z \leq 5$ have one fully spin-polarized ground state configuration whereas for $6\leq Z \leq 10$ one intermediate fully spin-polarized configuration with an orbital of 2p_0 type occurs.

physics.atom-ph↗

arXiv1999

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 γ>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.

physics.atom-ph↗

arXiv1999

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.

physics.atom-ph↗

arXiv1998

The ground state of the Lithium atom in strong magnetic fields

The ground and some excited states of the Li 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 10^8 T. With increasing field strength the ground state undergoes two transitions involving three different electronic configurations: for weak fields the ground state configuration arises from the field-free 1s^22s configuration, for intermediate fields from the 1s^22p_{-1} configuration and in high fields the 1s2p_{-1}3d_{-2} electronic configuration is responsible for the properties of the atom. The transition field strengths are determined. Calculations on the ground state of the Li+ ion allow us to describe the field-dependent ionization energy of the Li atom. Some general arguments on the ground states of multi-electron atoms in strong magnetic fields are provided.

physics.atom-ph↗