Journal of Atomic, Molecular, Condensed Matter and Nano Physics

Ionization of the $1S$ and $nS$ States of the Atomic Hydrogen by Positron and Electron Impacts

A. K. Bhatia — Sun, 26 Oct 2025 00:00:00 +0000

The ionizations of the $1S$ and $nS$ states of the atomic hydrogen have been carried out using the hybrid theory, which is variationally correct and has been obtained by modifying the method of polarized orbitals. Earlier, we calculated cross sections of exciting the higher states from the ground state, and cross sections of photoabsorption. Now, we apply the same approach to the ionization of states. The distortion of the orbit is considered due to the incident positron or electron. The distortion takes place whether the incident particle is outside or inside the orbit. Temkin considered distortion of the target electron only when the incident particle is outside the orbit of the target. However, there is no simple way to consider distortion of $nS$ states of atomic hydrogen. The cross sections are calculated by considering the distortion in the initial state as well as in the final state only in the $1S$ state and are compared with the previous calculations and the experimental results. The present cross sections have a maximum at an energy which is the same as the incident energy in the experimental results.

Variational Principles and Their Applications

A. K. Bhatia — Sun, 26 Oct 2025 00:00:00 +0000

There are many variational calculations of energies of various systems which have applications in Rydberg states and polarizabilities of these systems. There are variational calculations of scattering functions which have applications in calculations of excitation, photoabsorption, and radiative attachment cross sections. A few of these applications are mentioned.

New $Q$-$\beta$-Decay Theory Applied to the Calculations of the Rest Mass Energy $m_0c^2$ of the Electron and of the $Q$-Value for $\beta^+$-Decay Transitions in Mirrors Nuclei $A = 2Z - 1$

I. Sakho — Sun, 26 Oct 2025 00:00:00 +0000

A new nuclear approach named $Q$-$\beta$-decay theory $(Q\beta T)$ is presented. This method is applied to express theoretically the $\beta^+$-$Q$-value for mirrors nuclei $A = 2Z-1$. An important parameter named nuclear charge distribution coefficient (NCDC) noted $\alpha (Z)$ is presented. In the framework of the liquid drop nuclear model where the nuclear charge is uniformly distributed in the nuclear volume, $\alpha (Z) = 3/5$. It this work, it is demonstrated that the protons are not rigorously uniformly distributed within the nucleus. A slight correction is obtained with $\alpha (Z) \approx \alpha_0 = 3/5 + 0.0557$. For ${}^{37}$K and ${}^{65}$As, we find for the electron rest mass energy $m_0c^2=0.510$ 996 MeV agreeing excellently with the recommended value 0.510 998 950 MeV (CODATA, 2022). In addition, the $Q$-value calculated for $A$ ranging between 11 and 99 agree very well with the recent Atomic Mass Evaluation -- AME2020 (Wang et al. [15]). New accurate $Q$-values are tabulated for nuclei mirrors with $A$ ranging between 101 and 199. The present $Q$-$\beta$-DT make it possible to understand many nuclear properties and phenomena depending on the $Q$-value such as comparison between experimental and theoretical predictions of atomic masses, the understanding of the weak force and of the competitive processes between electron capture and $\beta^+$-decay.

Dilaton Detection in Radio Regions

Ankur Chaubey, Avijit K. Ganguly — Sun, 26 Oct 2025 00:00:00 +0000

Structure formation is a very important phenomena to follow the cosmological evolution of our universe. The role of ultra-light dark matter in this whole process is substantial.\ Keeping this point in view, one anticipates that the extremely light dilatons can be expected play it's part in this crucial process.\ The detection of the light dilatons is however not very easy, their cosmological signal may be detected in large radio telescopes.\ Using radiometer equation we ealborate on the possibility of detecting dilaton signal coming from the dark matter halo of nearby galaxies.\ Our analysis shows that in some parameter range the possibility of their detection is non-negligible.

4F and 5F Excitations of Atomic Hydrogen by Electron Impact

A. K. Bhatia — Sun, 26 Oct 2025 00:00:00 +0000

The excitation cross-sections of the 4F and 5F states of atomic hydrogen by electron impact have been calculated at incident energies 1.00 to 42.25 Ry, using the hybrid theory, which is variationally correct. The present calculation is a single-channel or a distorted wave calculation. Partial waves ranged from $L=3$ to 14 to obtain converged results. Excitations of higher states are needed for diagnostics of the solar and astrophysical plasmas. They are also needed to model plasma in fusion research, because they indicate the possibility that a state will be excited to a higher state when colliding with another state. Transition rates to the lower states can be measured by observing decays of the excited states.

Excitation of $(1s2s)$ $^{1}S$, the Singlet State of Helium Atoms by Positron Impact

A. K. Bhatia — Sun, 26 Oct 2025 00:00:00 +0000

The excitation of the $(1s2s)$ ${}^{1}S$ state of a helium atom has been calculated using scattering functions obtained by the method of polarized orbitals. In this method, the distortion of each orbital is considered due to the presence of the incident particle. The distortion takes place only when the incident particle is outside the target orbital. This method has been widely used in the scattering of electrons and positrons from various targets. Plane-wave normalization of the continuum function is considered, while it has been neglected in calculations carried out by Mandal et al. [1], and Willis and McDowell [3]. Consequently, the present results are higher than those obtained by them.

Journal of Atomic, Molecular, Condensed Matter and Nano Physics

Ionization of the \(1S\) and \(nS\) States of the Atomic Hydrogen by Positron and Electron Impacts

Variational Principles and Their Applications

New \(Q\)-\(\beta\)-Decay Theory Applied to the Calculations of the Rest Mass Energy \(m_0c^2\) of the Electron and of the \(Q\)-Value for \(\beta^+\)-Decay Transitions in Mirrors Nuclei \(A = 2Z - 1\)

Dilaton Detection in Radio Regions

4F and 5F Excitations of Atomic Hydrogen by Electron Impact

Excitation of \((1s2s)\) \(^{1}S\), the Singlet State of Helium Atoms by Positron Impact