Potential Model Theory Research Articles

Theoretical Study of Energy Levels and Transition Probabilities of Singly Ionized Aluminum (Al II)

Within the Weakest Bound Electron Potential Model (WBEPM) theory, calculations for energy levels and transition probabilities of singly ionized aluminum (Al II) are performed, and good agreement with experimental or accepted values is obtained. To treat properly the perturbed states, foreign perturbers are taken into account in studying the energy levels, meanwhile, a set of coupled equations is employed to determine the parameters effective nuclear charge Z ', effective principal quantum number n ', and effective angular quantum number l ' needed for the calculation of transition probabilities.

Low-energy photodisintegration of the deuteron and Big-Bang nucleosynthesis

The photon analyzing power for the photodisintegration of the deuteron was measured for seven gamma-ray energies between 2.39 and 4.05 MeV using the linearly polarized gamma-ray beam of the high-intensity gamma-ray source at the Duke Free-Electron Laser Laboratory. The data provide a stringent test of theoretical calculations for the inverse reaction, the neutron–proton radiative capture reaction at energies important for Big-Bang nucleosynthesis. Our data are in excellent agreement with potential model and effective field theory calculations. Therefore, the uncertainty in the baryon density ΩBh2 obtained from Big-Bang Nucleosynthesis can be reduced at least by 20%.

Study on energy levels of atom neon

In this article, energy levels of atom neon are studied systematically using the weakest bound electron potential model theory. Under the concept of spectrum-level-like series, energy levels are expressed as a function of principal quantum number. In the calculation, the perturbations among different series are included. The results of 1s 22s 22p 5( 2P 3/2 o )ns, 1s 22s 22p 5( 2P 3/2 o )np and 1s 22s 22p 5( 2P 3/2 o )nd series are given and compared with experimental values. Deviations between the present results and experimental values are generally less than 1 cm −1.

Systematical study on the ionization potential of excited states in carbon-like sequence

Ionization potential of excited states have been calculated for the 1s 22s 22p 2 3P 2, 1s 22s 22p3s 3P 0 2, 1s 22s 22p3d 3D 0 3, 1s 22s 22p3d 1F 0 3, and 1s 22s 22p4d 3D 0 3 series of carbon-like sequence from Z=6 to Z=23 on the basis of the weakest bound electron potential model theory and the concept of iso-spectrum-level series. In the calculation, the non-relativistic weakest bound electron potential model theory is used to calculate the non-relativistic energies and a fourth-order polynomial in nuclear charge Z is employed to evaluate the relativistic correction. Calculated values are compared with the experimental compiled results. Agreement with the experimental compiled results is generally within 0.1%.

Transition probabilities for Ne II

The Weakest Bound Electron Potential Model (WBEPM) theory is employed to calculate transition probabilities for Ne II in this paper. The parameters Z *, n * and l * are determined through fitting the experimental value of energy level and the expectation value of radial distance. Compared with most experimental results presently available and the values of critical compilation, the present results are accurate and in good agreement with them. Simple calculation procedure and accurate results can be both obtained from the present method.

ANALYZING POWER FOR THE PHOTODISINTEGRATION OF THE DEUTERON BETWEEN Eγ = 2.4 AND 4.0 MEV

The photon analyzing power for the photodisintegration of the deuteron was measured for seven gamma-ray energies between 2.39 and 4.05 MeV using the linearly polarized gamma-ray beam of the High-Intensity Gamma-ray Source at the Duke Free-Electron Laser Laboratory. The data provide a stringent test of theoretical calculations for the inverse reaction, the neutron-proton radiative capture reaction at energies important for Big-Bang nucleosynthesis. Our data are in excellent agreement with potential model and effective field theory calculations.

Ionization potential of excited states of Be‐like sequence in the concept of iso‐spectrum‐level series

AbstractWith the introduction of the concept of the iso‐spectrum‐level series, a linear relationship is found between the first differences of the ionization potential of excited states and nuclear charge Z along an iso‐spectrum‐level series, and the ionization potential of excited states of Be‐like sequence are studied systematically on the basis of the weakest bound electron potential model theory. The expression of nonrelativistic ionization potential is derived from the weakest bound electron potential model theory, and relativistic effects are included by using a fourth‐order polynomial in Z. As a demonstration, the ionization potentials of [He]2s2p 3P, [He]2s3s 1S0, [He]2s3p 1P, [He]2s3d 1D2, and [He]2s4d 1D2 series for a range of Be‐like sequence from Z = 4–23 are calculated. The results are compared with the experimental data and the recent sophisticated ab initio results. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 93: 344–350, 2003

Theoretical calculation of transition probabilities in neutral fluorine

The weakest bound electron potential model (WBEPM) theory is used to calculate transition probabilities for individual lines in neutral fluorine, for which transition probability data are scarce. A coupled equation concerning energy ε and the radial expectation value 〈 r〉 of the weakest bound electron is proposed to determine the parameters used in the calculation of transition probability. The accuracy of present results has been tested from comparisons with the most theoretical or experimental results presently available.

Calculation of High Rydberg Levels of Atom Zn with the WBEPM Theory

Within the weakest bound electron potential model theory, we treat the many-valance electron system of atom Zn as single electron system and use the extended martin's expression to determine parameters. The results are satisfying with deviations no more than 1 cm -1 compared with the experimental values.

Radiative Lifetimes and Atomic Transition Probabilities for Atomic Carbon and Oxygen

In this paper, the weakest bound electron potential model (WBEPM) theory is employed to calculate radiative lifetimes, transition probabilities, and oscillator strengths for atomic carbon and oxygen. Results for the lifetimes, transition probabilities, and oscillator strengths of individual lines are reported and compared with theoretical and experimental results currently available. In order to test the accuracy of our results further, oscillator strengths for multiplets are also calculated, and results are compared with other theoretical or experimental results. The good agreement obtained in comparison shows that present method with a simple approach is reliable.

Theoretical resonance transition probabilities and lifetimes for atomic nitrogen

In this paper, resonance transition probabilities and radiative lifetimes of atomic nitrogen are calculated employing the weakest bound electron potential model (WBEPM) theory. In the calculation, a coupled equation concerning the 〈 r〉 and the energy of the weakest bound electron is used to determine parameters Z ∗,n ∗ , and l ∗ . With these parameters, matrix element can be evaluated. And then, lifetimes and transition probabilities can be further obtained. The accuracy of present results has been tested from comparisons with the most accurate theoretical or experimental results presently available.

Theoretical Study of Transition Probability for Oxygen Atom and Ions

Using the Weakest Bound Electron Potential Model Theory, the problem of many-electron systems is simplified as a single-electron problem. Transition probabilities of oxygen atom and oxygen ions (O ...

Identification of oxidizing agents in aqueous amine–CO 2 systems using a mechanistic corrosion model

The purpose of this paper was to perform studies in order to obtain a better understanding of corrosion in an aqueous amine–CO 2 environment. A mechanistic corrosion model, built as a fortran-90 program, is established to identify the oxidizing agents responsible for corrosion reactions. The model incorporates the rigorous electrolyte nonrandom two-liquid (NRTL) equilibrium model and mixed potential theory in order to simulate the concentrations of chemical species and polarization behavior taking place at a metal–solution interface. The simulation results, based on monoethanolamine (MEA) system, indicates that bicarbonate ion (HCO 3 −) and water (H 2O) are the primary oxidizing agents and hydrogen ion (H +) or hydronium ion (H 3O +) plays an insignificant role in the reduction reaction.

Simple method for the precise calculation of atomic energy levels of IB elements in the periodic table

AbstractDue to the complicated and typical electronic structure of atoms and ions of the IB group in the periodic table, theoretical calculation of their atomic energy levels has important theoretical and practical significance. In this article, the theoretical calculation of atomic energy levels of the atoms of IB group in the periodic table was completed for the first time within the scheme of the weakest bound electron potential model theory. The results were compared with experimental values and the deviations are about 0.1–1 cm−1. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002

Calculation of the transition probability for C (I- IV)

A theory, called the weakest bound electron potential model theory, is employed in a study of the transition probabilities of C i, C ii, C iii, and C iv. A coupled equation that relates energy ε and radial expectation value 〈r〉NL of the weakest bound electron is proposed for determining the parameters used in the calculation of the transition probability. The results presented are in agreement with the accepted values, and the agreement with is within experimental uncertainties.

Strain effect in large silicon nanocrystal quantum dots

We present a computer simulation of strain effects on the electronic spectrum of 100 Å diam Si nanocrystal (nc-Si) quantum dots embedded in SiO2, based on the continuum strain model and deformation potential theory. We show that the coupling between the nc-Si geometry and the symmetry generated by the strain potential can enhance confinement in the quantum dot and can lift the degeneracy of the conduction band valleys for nonspherically symmetric nanocrystals.

A novel FTIR method for studying mixed gas adsorption at low concentrations: H 2O and CO 2 on NaX zeolite and γ-alumina

The modeling and measurement of mixed gas adsorption at low concentrations (ppm level) is an important part of the design of an adsorptive purification process, but has received little attention so far. This work introduces a new technique for the measurement of the equilibrium adsorbed amounts of a multicomponent mixture of gases/vapors on an adsorbent pellet based on Fourier-transform infrared spectroscopy (FTIR). The technique consists of first calibrating the infrared absorption peak areas with known adsorbed amounts of the different components in the adsorbate mixture using single gases/vapors. By measuring the IR peak areas of the adsorbates on the sorbent in contact with the gas mixture, the actual amounts of the sorbate can be determined. The method is fairly simple, quick, and accurate even at low concentrations provided the adsorbates exhibit strong distinct peaks and the sorbent is at least partially infrared-transparent. The utility of this method is demonstrated by measuring the binary gas adsorption of CO 2 and H 2O-vapor at low concentrations on two adsorbents: 13X (NaX) zeolite molecular sieve, and γ-Al 2O 3. In the low CO 2 concentration range, the amount of CO 2 adsorbed seemed to be significantly enhanced in the presence of H 2O in trace amounts. The adsorption data was fit to the Doong–Yang potential theory model, and the ideal (and real) adsorbed solution theory (IAS) of Myers and Prausnitz, with the Dubinin–Astakhov equation as the basis.

Sorbents for air prepurification in air separation

Air fed to air separation units such as cryogenic distillation columns needs to be prepurified; that is, the concentration levels of air-borne impurities such as water vapor, CO 2, and light hydrocarbons need to be brought down below the tolerable limits. This process is commonly carried out by using adsorptive methods such as pressure swing adsorption (PSA) or temperature swing adsorption (TSA). This work deals with the study of adsorption characteristics of two conventional microporous adsorbents, namely 13X zeolite molecular sieves, and activated γ-Al 2O 3, and three non-conventional adsorbents, namely a natural zeolite (clinoptilolite), and its K +- and Ca 2+-ion exchanged forms. A noteworthy feature of this work is the measurement of adsorption isotherms at very low partial pressures of the adsorbate gas (to a few ppm). The relative merits of these adsorbents for the removal of trace amounts of water vapor, CO 2, and hydrocarbons such as CH 4, C 2H 4, and C 2H 6 are discussed. The isotherm data for 13X zeolite and γ-Al 2O 3 has been fit to the Langmuir–Freundlich, Tòth, and Dubinin–Astakhov (DA, or potential theory) isotherm models. It has been found that the potential theory model is the most suitable one for description of low pressure or concentration data. The origin of the better fit by potential theory is that its corresponding energy distribution function follows a quasi-Gaussian distribution with a broadening at high adsorption energies, and the high-energy sites are important for adsorption at low pressures or concentrations. Finally, the possibility of using H 2O adsorption isotherm to evaluate the pore size distribution by the Horvàth–Kawazoe approach is discussed.

Transition probability of Cu I, Ag I, and Au I from weakest bound electron potential model theory

In this paper, the weakest bound electron potential model (WBEPM) theory is employed to study the transition probability of many-valence-electron systems Cu I, Ag I, and Au I. According to this theory, a coupled equation is used to obtain the parameters Z*, n*, and l*, which are needed in the calculation of transition probability. In the calculation, spectral fine structure is taken into consideration, and node numbers of silver and gold are adjusted. Compared with the accepted values, the results reported here are fairly good, and agreement is within the uncertainty of the accepted values. In our discussion, we give the explanation of node number adjustment from the view of WBEPM theory.

Analysis of the bound odd-parity spectrum of krypton by weakest bound electron potential model theory

Within the weakest bound electron potential model theory, the J=0,1,2,3,4,5 odd bound levels of neutral krypton are classified by spectrum-level-like series. In our previous work, we employed Martin's formula to calculate the quantum defects for the unperturbed spectrum-level-like series and obtained excellent results. For the perturbed series, however, extra- or interpolation using Martin's formula may lead to serious error. We, therefore, propose a quantum defect formula to fit the perturbed series by combining Martin’s formula with Langer's. The regularity of spectrum-level-like series is investigated with the revised Martin formula. Great agreement with experimental values is obtained, and the deviations between the calculated values and experimental ones are less than 1 cm −1. Meanwhile, some unknown level positions are predicted.