scholarly journals The nuclear β -spectra of thorium B→C and C→C', and the intensities of some β -ray lines of thorium (B+C+C")

1948 ◽  
Vol 195 (1042) ◽  
pp. 287-300 ◽  
Keyword(s):  
Internal Conversion ◽  
Conversion Coefficient ◽  
Energy Transition ◽  
Detailed Comparison ◽  
High Energy ◽  
Internal Conversion Coefficient ◽  
Dipole Radiation ◽  
Allowed Transition ◽  
Forbidden Transitions ◽  
High Energy Transition

The β -spectra of Th(C+C") and Th(B+C+C") have been measured using semicircular focusing. The sources were mounted between two thin films to prevent the escape of ThC" by α -recoil. The intensities of seven of the β -ray lines were measured and the continuous spectra of ThB. C and ThC. C' were found by subtraction using the known spectrum of ThC". D. The β -ray end-point of ThC. C' is at 2·250 MeV, and the shape of the β -ray spectrum differs but little from that of an allowed transition for energies above 0·9 MeV. A detailed comparison is made with the shape of the compound spectrum required to account for the known γ -rays of ThC', using the theory of forbidden transitions. A spin change of ∆ I = ± 2 is ruled out, but ∆ I = 0 or ± 1 is possible. The β -spectrum of Th B seems to be composite with its principal end-points at 0·331 and 0·569 MeV. The intensity of the high-energy transition between the ground states is about 0·12 ± 0·02 electrons per disintegration. The K internal conversion coefficient of the F γ -ray was found to be about Q·377, 16% higher than the theoretical value for magnetic dipole radiation.

scholarly journals The internal conversion coefficient for radium C

1932 ◽  
Vol 138 (836) ◽  
pp. 643-664 ◽  
Keyword(s):  
Internal Conversion ◽  
Conversion Coefficient ◽  
Atomic System ◽  
Relativistic Equation ◽  
High Energy ◽  
Internal Conversion Coefficient ◽  
Γ Rays ◽  
Γ Ray ◽  
Charged Nucleus ◽  
Special Case

It is well known that the γ-rays emitted from a radio­active nucleus are often partially absorbed by the atomic system, giving rise to secondary β-rays. From observations of the resultant γ-ray intensity, and that of the β-rays, it is possible to infer the proportion of γ-rays reabsorbed in the atomic system. This factor is called the “internal conversion co­efficient.” Its theoretical value has been discussed by Miss Swirles and R. H. Fowler. Miss Swirles treats the nucleus as an oscillating Hertzian doublet, radiating classically, and considers the radiation field as producing photoelectric transitions in the planetary electrons, according to the Schrodinger theory. The rate of emission of γ-rays from the nucleus is taken to be the classical rate of radiation of energy by the dipole, divided by hv . The values obtained in this way were about 10 times too small, except for the γ-ray of energy 14.26 x 10 5 e. v., which has an internal conversion coefficient several hundred times that given by the theory. This special case has been discussed by Fowler ( loc . cit .), and we shall not consider it here. An obvious defect in the theory is the use of Schrödinger’s equation, which may not be expected to hold so near the nucleus, or for electrons of such high energy. It therefore seemed possible that the more correct, relativistic equation of Dirac might give results in accordance with experiment in the majority of cases, and the calculation has been carried out by Casimir. The same model is used, and, for purposes of calculation, the interaction of the other electrons is neglected, so that we have a single electron in the field of a charged nucleus. For the β-rays emitted from the K-shell, we may take the actual nuclear charge in carrying out the calculation. In the case of extremely hard γ-rays, whose energies may be considered large compared with mc 2 , it is legitimate to use the asymptotic expansion for the wave function repre­senting the β-ray. If we apply this theory to the range covered by experiment, we obtain results (Casimir, loc. cit. ) which are still much too small, so that we were tempted to attribute the bulk of the conversion to some special type of interaction with the nucleus. It seems fairly certain that this must be the case for the γ-ray with hv = 14.26 x 10 5 e. v., which has an abnormally high internal conversion coefficient.

Total internal conversion coefficient of the 260.9 keV (7+→3−) transition in198mTl

1986 ◽  
Vol 91 (4) ◽  
pp. 352-358 ◽  
Author(s):  
N. Venkateswara Rao ◽  
Ch. Suryanarayana ◽  
D. G. S. Narayana ◽  
S. Bhuloka Reddy ◽  
G. Satynarayana ◽  
...  
Keyword(s):  
Internal Conversion ◽  
Conversion Coefficient ◽  
Internal Conversion Coefficient

STUDIES ON NUCLEOPHILIC SUBSTITUTION REACTIONS AT CARBON (SN2(C)) AND SILICON (SN2(Si)) IN TERMS OF AB INITIO, POTENTIAL, ACTING ON AN ELECTRON IN A MOLECULE AND MOLECULAR FACE THEORY

2009 ◽  
Vol 08 (supp01) ◽  
pp. 983-1001 ◽  
Author(s):  
YAN-LI DING ◽  
LI-DONG GONG ◽  
DONG-XIA ZHAO ◽  
MING-BO ZHANG ◽  
ZHONG-ZHI YANG
Keyword(s):  
Ab Initio ◽  
Nucleophilic Substitution ◽  
Gas Phase ◽  
Chemical Bond ◽  
Energy Transition ◽  
High Energy ◽  
Ab Initio Method ◽  
Substitution Reactions ◽  
Nucleophilic Substitution Reactions ◽  
High Energy Transition

The gas-phase identity bimolecular nucleophilic substitution reactions, Cl- + CH3 Cl → ClCH3 + Cl- and Cl- + SiH3Cl → ClSiH3 + Cl- , are investigated in terms of the ab initio method, potential acting on an electron in a molecule (PAEM) and molecular face (MF) theory. The computations have been performed at the CCSD(T)/aug-cc-pVTZ//MP2/6-311+G(3df,3pd) and CISD/aug-cc-pVDZ level. Based on the ab initio calculation, according to the PAEM theory, the strength of a chemical bond during forming or rupturing may be characterized by the D pb , which is a new physical quantity relating to the barrier height of the PAEM along a chemical bond. According to the MF theory, the interesting pictures of electron transfer and interpolarization effect between the reactants are clearly demonstrated to provide visualized spatial changing features of the MF for the title reactions along the IRC routes. The reason why [ Cl⋯CH3⋯Cl]- is a high-energy transition state is also analyzed in comparison with the stable low-energy intermediate [ Cl⋯SiH3⋯Cl]- .

ON THE NUMERICAL CALCULATION OF THE INTERNAL CONVERSION IN THE K-SHELL—THE ELECTRIC DIPOLE CASE

1949 ◽  
Vol 27a (2) ◽  
pp. 17-25 ◽  
Author(s):  
J. P. Stanley
Keyword(s):  
Numerical Calculation ◽  
Electric Dipole ◽  
Internal Conversion ◽  
Conversion Coefficient ◽  
Internal Conversion Coefficient ◽  
Γ Radiation ◽  
Variable Formula

Hulme's formula for the internal conversion of γ-radiation is simplified and used to calculate the internal conversion coefficient in the electric dipole case for electrons in the K-shell. For each of the elements Z = 69, 74, 79, 84, 89, IK is calculated for 10 values of the variable [Formula: see text] and a table obtained by interpolation is given for θ = 0.05 to θ = 1.70.

Standardization and determination of the total internal conversion coefficient of In-111

2014 ◽  
Vol 87 ◽  
pp. 192-194 ◽  
Author(s):  
Izabela T. Matos ◽  
Marina F. Koskinas ◽  
Tatiane S. Nascimento ◽  
Ione M. Yamazaki ◽  
Mauro S. Dias
Keyword(s):  
Internal Conversion ◽  
Conversion Coefficient ◽  
Internal Conversion Coefficient

The Decay of 169Yb

1972 ◽  
Vol 50 (19) ◽  
pp. 2348-2354 ◽  
Author(s):  
S. K. Sen ◽  
D. L. Salie ◽  
E. Tomchuk
Keyword(s):  
Direct Measurement ◽  
Gamma Rays ◽  
Internal Conversion ◽  
Gamma Ray ◽  
Conversion Coefficient ◽  
Coulomb Excitation ◽  
Internal Conversion Coefficient ◽  
Electron Capture Decay ◽  
Upper Limits ◽  
First Time

The decay of 169Yb was investigated using several Ge(Li) detectors of different sizes. The following gamma rays (energies in keV and intensities within brackets) were definitely identified with the 169Yb decay: 20.7 (0.66 ± 0.04), 63.1 (124 ± 5), 93.6 (7.2 ± 0.3), 109.8 (50 ± 2), 117.3 (0.08 ± 0.04), 118.2 (5.4 ± 0.2), 130.5 (34 ± 2), 156.7 (0.023 ± 0.004), 177.2(59 ± 3), 198.0 (100), 240.4 (0.33 ± 0.02), 261.0 (4.7 ± 0.2), and 307.7 (28 ± 1). The recently reported weak gamma-ray peaks at 515 (0.008 ± 0.002) and 625 (0.010 ± 0.002) were also observed and could not be ruled out as not belonging to 169Yb. The recently reported gamma-ray peaks at 140, 160, 207, 288, 295, 316, 320, 328, 355, 371, 379, 396, and 417 were detected and shown not to be from the decay of 169Yb while those at 218, 229, 285, 304, 335, 388, 411, and 425 were not observed and upper limits were placed on their intensities. The presence of very weak peaks at 515 and 625 establishes the formation of the 633 keV state of 169Tm following electron capture decay of 169Yb as reported by George. (This level has been previously observed only in Coulomb excitation of 169Tm.) The total internal conversion coefficient for the 20.7 keV transition was determined for the first time from the direct measurement of the gamma-ray intensity as 51 ± 10 corresponding to an M1 transition.

scholarly journals The high‐energy transition state of the glutamate transporter homologue GltPh

2020 ◽  
Vol 40 (1) ◽  
Author(s):  
Gerard H M Huysmans ◽  
Didar Ciftci ◽  
Xiaoyu Wang ◽  
Scott C Blanchard ◽  
Olga Boudker
Keyword(s):  
Transition State ◽  
Glutamate Transporter ◽  
Energy Transition ◽  
High Energy ◽  
High Energy Transition
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