Application of the two state approximation to positronium formation in hydrogen

1977 ◽  
Vol 55 (16) ◽  
pp. 1393-1398 ◽  
Author(s):  
V. S. Kulhar ◽  
C. S. Shastry
Keyword(s):  
Charge Exchange ◽  
Cross Sections ◽  
Energy Region ◽  
Hydrogen Charge ◽  
Time Dependent ◽  
Quantum Mechanical ◽  
High Energies ◽  
Mechanical Formalism ◽  
State Approximation ◽  
Quantum Mechanical Formalism

A generalized form of Band's theory for rearrangement collisions based on the two state approximation in time dependent quantum-mechanical formalism is used to investigate the positron hydrogen charge exchange problem. The formalism takes into account the nonorthogonality of the rearrangement channel. The effect of nonorthogonality is to raise the cross sections from first Born results. At high energies our results approach Born results. Comparison with other calculations is also reported in the energy region 1.5 to 10 Ry.

Excited states of positronium in positron–hydrogen charge exchange

1978 ◽  
Vol 56 (5) ◽  
pp. 565-570 ◽  
Author(s):  
V. S. Kulhar ◽  
C. S. Shastry
Keyword(s):  
Excited States ◽  
Charge Exchange ◽  
Cross Sections ◽  
Ground State ◽  
Born Approximation ◽  
Energy Region ◽  
Hydrogen Charge ◽  
Positronium Formation ◽  
State Approximation ◽  
Higher Excited States

The two state approximation method for the study of the rearrangement collisions is applied to the process of positronium formation in excited states for positron–hydrogen charge exchange collisions. Differential and integrated cross sections are computed for positronium formation in 2S, 2P, and 3S excited states. The results obtained in the energy region 2 to 10 Ry are compared with positronium formation cross sections in ground state. Total positronium formation cross sections including the contributions of capture into all the higher excited states of positronium are also computed in the first Born approximation and the two state approximation in the energy region considered.

Charge Exchange Cross Sections of Hydrogen Particles in Gases at High Energies

1958 ◽  
Vol 109 (2) ◽  
pp. 355-359 ◽  
Author(s):  
C. F. Barnett ◽  
H. K. Reynolds
Keyword(s):  
Charge Exchange ◽  
Cross Sections ◽  
High Energies

Formation of antihydrogen in the ground state

2007 ◽  
Vol 85 (4) ◽  
pp. 393-399
Author(s):  
V S Kulhar
Keyword(s):  
Cross Sections ◽  
Ground State ◽  
Time Reversal ◽  
Exchange Process ◽  
Hydrogen Charge ◽  
High Energy ◽  
High Energy Region ◽  
Charge Exchange Process ◽  
State Approximation ◽  
Reversal Invariance

Cross sections for antihydrogen formation in the ground state for the process [Formula: see text] + Ps(nlm) → [Formula: see text](1s) + e– have been calculated using charge conjugation and time reversal invariance. Calculations are based on a two-state approximation method, used by the author earlier for positron–hydrogen charge -exchange process (e+ – H → Ps(nlm) + p). Cross-section results are reported in the intermediate- and high-energy region (20 keV – 500 keV). PACS No.: 36.10.Dr

scholarly journals On the role of entanglement in Schrödinger’s cat paradox

Open Physics ◽  
2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Stefan Rinner ◽  
Ernst Werner
Keyword(s):  
Radioactive Substance ◽  
The State ◽  
Entangled States ◽  
Quantum Mechanical ◽  
The Core ◽  
Mechanical Formalism ◽  
Quantum Mechanical Formalism ◽  
Cat States ◽  
Quantum Optical

AbstractIn this paper we re-investigate the core of Schrödinger’s “cat paradox”. We argue that one has to distinguish clearly between superpositions of macroscopic cat states |☺〉 + |☹〉 and superpositions of entangled states |☺, ↑〉 + |☹, ↓〉 which comprise both the state of the cat (☺=alive, ☹=dead) and the radioactive substance (↑=not decayed, ↓=decayed). It is shown, that in the case of the cat experiment recourse to decoherence or other mechanisms is not necessary in order to explain the absence of macroscopic superpositions. Additionally, we present modified versions of two quantum optical experiments as experimenta crucis. Applied rigorously, quantum mechanical formalism reduces the problem to a mere pseudo-paradox.

scholarly journals On the isotopic fingerprint exerted on carbonyl sulfide by the stratosphere

2012 ◽  
Vol 12 (9) ◽  
pp. 25329-25353 ◽  
Author(s):  
J. A. Schmidt ◽  
S. Hattori ◽  
N. Yoshida ◽  
S. Nanbu ◽  
M. S. Johnson ◽  
...  
Keyword(s):  
Cross Sections ◽  
Potential Energy Surfaces ◽  
Carbonyl Sulfide ◽  
Isotopic Fractionation ◽  
Data Sets ◽  
Mechanical Formalism ◽  
Model Study ◽  
Quantum Mechanical Formalism ◽  
Energy Surfaces ◽  
Good Agreement

Abstract. The isotopic fractionation in OCS photolysis is studied theoretically from first principles. UV absorption cross sections for OCS, OC33S, OC34S, OC36S and O13CS are calculated using the time-depedent quantum mechanical formalism and recent potential energy surfaces for the lowest four singlet and lowest four triplet electronic states. The calculated isotopic fractionations as a function of wavelength are in good agreement with recent measurements by Hattori et al. (2011) and indicate that photolysis leads to only a small enrichment of 34S in the remaining pool of OCS. A simple stratospheric model is constructed taking into account the main stratospheric sink reactions of OCS and it is found that stratospheric removal overall slightly favors light OCS in constrast to the findings of Leung et al. (2002). These results show, based on isotopic considerations, that OCS is an acceptable source of background stratosperic sulfate aerosol in agreement with a recent model study of Brühl et al. (2012). The 13C isotopic fractionation due to photolysis of OCS is significant and will leave a strong signal in the pool of remaining OCS making it a candidate for tracing using the ACE-FTS and MIPAS data sets.

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