Related papers: Ionization Potential of the Helium Atom
We report on a combined experimental and theoretical study of Li$^+$ ions solvated by up to 50 He atoms. The experiments show clear enhanced abundances associated with He$_n$Li$^+$ clusters where $n=2$, 6, 8, and 14. We find that classical…
Multiphoton ionization provides a clear window into the nature of electron correlations in the helium atom. In the present study, the final state energy range extends up to the region near the $N=2$ and $N=3$ ionization thresholds, where…
We theoretically study multiphoton ionization of the Ca atom irradiated by the second (photon energy 3.1 eV) and third (photon energy 4.65 eV) harmonics of Ti:sapphire laser pulses (photon energy 1.55 eV). Because of the dense energy level…
The QED contribution to the dipole polarizability of the $^4$He atom was computed, including the effect of finite nuclear mass. The computationally most challenging contribution of the second electric-field derivative of the Bethe logarithm…
We show that we can predict the first ionization energy of the carbon atom to within 0.872 cm$^{-1}$ of the experimental value. This is an improvement of more than a factor of 6.5 over the preceding best prediction in [Phys. Rev. A 81,…
The continuum of $^{10}$He nucleus is studied theoretically in a three-body $^{8}$He+$n$+$n$ model basing on the recent information concerning $^9$He spectrum [Golovkov, \textit{et al.}, Phys. Rev. C \textbf{76}, 021605(R) (2007)]. The…
A nuclear-elastic $^9$Be+$^4$He reaction is investigated. A tangential literature overview of the proximity potential is presented, necessitated by an approximate method for calculating $l\text{-values}$. The model is surveyed intensively,…
Tunnel ionization rates of triplet Rydberg states in helium with principal quantum numbers close to 37 have been measured in electric fields at the classical ionization threshold of $\sim197$ V/cm. The measurements were performed in the…
The successive ionization potentials (IPs) and electron affinities (EAs) for superheavy elements with $111 \leq Z \leq 114$, namely, Rg, Cn, Nh, and Fl are reexamined using the relativistic Fock-space coupled-cluster method with…
We report results for the ground-state energy and structural properties of small $^4$He-T$\downarrow$ clusters consisting of up to 4 T$\downarrow$ and 8 $^4$He atoms. These results have been obtained using very well-known $^4$He-$^4$He and…
On the basis of the perturbation theory in the fine structure constant $\alpha$ and the ratio of the electron to muon masses we calculate one-loop vacuum polarization and electron vertex corrections and the nuclear structure corrections to…
The pair potential for helium has been computed with accuracy improved by an order of magnitude relative to the best previous determination. For the well region, its uncertainties are now below 1 millikelvin. The main improvement is due to…
We study dissipation effects for electrons on the surface of liquid helium, which may serve as qubits of a quantum computer. Each electron is localized in a 3D potential well formed by the image potential in helium and the potential from a…
Three simple $7-, (7+3)-, 10-$parametric trial functions for the ${\rm H}_3^+$ molecular ion are presented. Each of them provides subsequently the most accurate approximation for the Born-Oppenheimer ground state energy among…
We report theoretical calculations of the diamagnetic susceptibility, $\chi_0$, of helium atom. We determined the complete relativistic correction to $\chi_0$ of the order of $\alpha^4$, where $\alpha$ is the fine structure constant, by…
A new state of the H$_2^+$ molecular ion with binding energy of 1.09$\times10^{-9}$ a.u. below the first dissociation limit is predicted, using highly accurate numerical nonrelativistic quantum calculations. It is the first L=0 excited…
The shift and broadening of the resonance lines in spectrum of the antiprotonic helium atoms $\bar{p}\mathrm{He}^{+}$ located in fluid and superfluid $^4$He have been calculated. The contributions to the shift and broadening from collective…
We theoretically investigate the single and double ionization of the He atom by antiproton impact for projectile energies ranging from $3$~keV up to $1000$~keV. We obtain accurate total cross sections by directly solving the fully…
The analysis of all published results on electrons and holes impact ionization coefficients in 4H-SiC at 300K have been performed. It is shown that the most plausible approximation of dependencies $\alpha_{n,p}$ on the electric field…
The energy levels of the $n=1$ and $n=2$ bound states of the $\mu^+\mu^-$ atom (true muonium) are calculated starting from a previously derived potential that correctly describes positronium to order $\alpha^5$ supplemented by the known…