Towards an Accurate Wave Function for Positronium Hydride

1969 ◽  
Vol 178 (1) ◽  
pp. 24-34 ◽  
Author(s):  
C. F. Lebeda ◽  
David M. Schrader
Keyword(s):  
Wave Function ◽  
Positronium Hydride ◽  
Accurate Wave

An improved wave function for positronium hydride: Preliminary report

1974 ◽  
Vol 3 (2) ◽  
pp. 159-160 ◽  
Author(s):  
Peter Nevin ◽  
D. M. Schrader ◽  
C. F. Lebeda
Keyword(s):  
Wave Function ◽  
Preliminary Report ◽  
Positronium Hydride

Improved wave function for positronium hydride

1974 ◽  
Vol 9 (5) ◽  
pp. 2248-2251 ◽  
Author(s):  
Peter B. Navin ◽  
D. M. Schrader ◽  
C. F. Lebeda
Keyword(s):  
Wave Function ◽  
Positronium Hydride

Effect of electron correlation in proton–helium collisions

2015 ◽  
Vol 24 (02) ◽  
pp. 1550009
Author(s):  
H. Ghavaminia
Keyword(s):  
Wave Function ◽  
Cross Sections ◽  
Electron Correlation ◽  
Intermediate Energy ◽  
Total Cross Sections ◽  
Helium Atoms ◽  
Single Electron Capture ◽  
Fast Protons ◽  
Theoretical Results ◽  
Accurate Wave

The four-body Born approximation is applied in post form to calculate the differential and total cross-sections for single electron capture from helium atoms by impact of the fast protons in the intermediate energy range. Theoretical results are obtained for hydrogen formation in ground state using full correlated accurate wave function for helium. The present results are compared with the results obtained from one parameter uncorrelated wave function to provide a clear visualization for the effect of electron correlation on the cross-sections. Comparison between the results for different wave functions shows the sensitivity of the processes on the electron–electron correlation especially at small scattering angles. The results are also compared with experimental data. The present calculated results show a general agreement with experimental finding for differential cross-sections and pursue the excellent trend with the measurement and other theoretical findings for total cross-sections.

scholarly journals Adiabatic connection from accurate wave-function calculations

2000 ◽  
Vol 112 (12) ◽  
pp. 5292-5297 ◽  
Author(s):  
Derek Frydel ◽  
William M. Terilla ◽  
Kieron Burke
Keyword(s):  
Wave Function ◽  
Accurate Wave

scholarly journals Hartree–Fock implementation using a Laguerre-based wave function for the ground state and correlation energies of two-electron atoms

2018 ◽  
Vol 376 (2115) ◽  
pp. 20170153 ◽  
Author(s):  
Andrew W. King ◽  
Adam L. Baskerville ◽  
Hazel Cox
Keyword(s):  
Wave Function ◽  
Ground State ◽  
Nuclear Charge ◽  
Analytical Form ◽  
Theoretical Chemistry ◽  
Variational Parameter ◽  
Isoelectronic Sequence ◽  
Hartree Fock ◽  
The One ◽  
Accurate Wave

An implementation of the Hartree–Fock (HF) method using a Laguerre-based wave function is described and used to accurately study the ground state of two-electron atoms in the fixed nucleus approximation, and by comparison with fully correlated (FC) energies, used to determine accurate electron correlation energies. A variational parameter A is included in the wave function and is shown to rapidly increase the convergence of the energy. The one-electron integrals are solved by series solution and an analytical form is found for the two-electron integrals. This methodology is used to produce accurate wave functions, energies and expectation values for the helium isoelectronic sequence, including at low nuclear charge just prior to electron detachment. Additionally, the critical nuclear charge for binding two electrons within the HF approach is calculated and determined to be Z HF C =1.031 177 528. This article is part of the theme issue ‘Modern theoretical chemistry’.

Analytic integration of contrast transfer functions

1988 ◽  
Vol 46 ◽  
pp. 822-823
Author(s):  
Peter Rez
Keyword(s):  
Wave Function ◽  
Transfer Function ◽  
Transfer Functions ◽  
Spherical Aberration ◽  
Continuous Distribution ◽  
Objective Lens ◽  
Direction Parallel ◽  
Scattering Angle ◽  
Analytic Integration ◽  
Image Position

In high resolution microscopy the image amplitude is given by the convolution of the specimen exit surface wave function and the microscope objective lens transfer function. This is usually done by multiplying the wave function and the transfer function in reciprocal space and integrating over the effective aperture. For very thin specimens the scattering can be represented by a weak phase object and the amplitude observed in the image plane is1where fe (Θ) is the electron scattering factor, r is a postition variable, Θ a scattering angle and x(Θ) the lens transfer function. x(Θ) is given by2where Cs is the objective lens spherical aberration coefficient, the wavelength, and f the defocus.We shall consider one dimensional scattering that might arise from a cross sectional specimen containing disordered planes of a heavy element stacked in a regular sequence among planes of lighter elements. In a direction parallel to the disordered planes there will be a continuous distribution of scattering angle.

Atomic Imaging of Crystals using Large-Angle Electron Scattering in STEM

1990 ◽  
Vol 48 (1) ◽  
pp. 74-75
Author(s):  
D.E. Jesson ◽  
S. J. Pennycook
Keyword(s):  
Wave Function ◽  
Electron Scattering ◽  
Numerical Solutions ◽  
Large Angle ◽  
Real Space ◽  
High Angle ◽  
Analytical Treatment ◽  
Order Zero ◽  
Experimental Conditions ◽  
Ewald Sphere

It is well known that conventional atomic resolution electron microscopy is a coherent imaging process best interpreted in reciprocal space using contrast transfer function theory. This is because the equivalent real space interpretation involving a convolution between the exit face wave function and the instrumental response is difficult to visualize. Furthermore, the crystal wave function is not simply related to the projected crystal potential, except under a very restrictive set of experimental conditions, making image simulation an essential part of image interpretation. In this paper we present a different conceptual approach to the atomic imaging of crystals based on incoherent imaging theory. Using a real-space analysis of electron scattering to a high-angle annular detector, it is shown how the STEM imaging process can be partitioned into components parallel and perpendicular to the relevant low index zone-axis.It has become customary to describe STEM imaging using the analytical treatment developed by Cowley. However, the convenient assumption of a phase object (which neglects the curvature of the Ewald sphere) fails rapidly for large scattering angles, even in very thin crystals. Thus, to avoid unpredictive numerical solutions, it would seem more appropriate to apply pseudo-kinematic theory to the treatment of the weak high angle signal. Diffraction to medium order zero-layer reflections is most important compared with thermal diffuse scattering in very thin crystals (<5nm). The electron wave function ψ(R,z) at a depth z and transverse coordinate R due to a phase aberrated surface probe function P(R-RO) located at RO is then well described by the channeling approximation;

DEUTERON: WAVE FUNCTION AND PARAMETERS

2014 ◽  
Vol 36 (0) ◽  
pp. 100-106 ◽  
Author(s):  
І. І. Гайсак ◽  
В. І. Жаба
Keyword(s):  
Wave Function ◽  
Deuteron Wave Function
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