Calculation of singlet and triplet energy states of the two-dimensional (2D) H– ion and 2D He atom

Atoms and molecules with a reduced dimension can arise in large external magnetic fields. The magnetic traps were used by Görlitzet al1 in order to transfer sodium atoms to lower dimensional states. Transitions of sodium atoms in both two-dimensional (2D) and onedimensional (1D) state were realized. Super strong magnetic fields can occur in the plasma of the Sun and stars. Therefore, in principle, one can observe the spectra of two-dimensional atoms and molecules in them. As is well known, on the Sun and Sun-like stars, the atoms of hydrogen and Helium lead to a small absorption of light. The main absorption provides a negative hydrogenion.2 Metal atoms make a small contribution to absorption, since their number is tens of thousands of times smaller than those of hydrogen atoms. Such a negative ion is formed when a second electron is attached to a hydrogen atom. The numerical research of anisotropic characteristics of a two-dimensional (2D) hydrogen atom induced by a magnetic field was carried out for Koval et al.3 Under terrestrial conditions, Н– ions are unstable due to their extremely high chemical activity. A complete analog of the H– in semiconductor crystals is the D–center with a negative charge, i.e. a shallow hydrogen-like donor center that has captured an additional electron. The development of nanotechnologies has led to the emergence of new materials, such as two-dimensional monoatomic layers of various compositions. Graphene is a well-known example of a crystal with a two-dimensional hexagonal lattice in which one atom forms each vertex. There are other materials with a structure close to graphene.4,5 In such materials, it is possible to observe twodimensional analogues of D– centers in three-dimensional