11 research outputs found
A study of the almost sequential mechanism of true ternary fission
We consider the collinear ternary fission which is a sequential ternary decay
with a very short time between the ruptures of two necks connecting the middle
cluster of the ternary nuclear system and outer fragments. In particular, we
consider the case where the Coulomb field of the first massive fragment
separated during the first step of the fission produces a lower pre-scission
barrier in the second step of the residual part of the ternary system. In this
case, we obtain a probability of about for the yield of massive
clusters such as \nuclide[70]{Ni}, \nuclide[80-82]{Ge}, \nuclide[86]{Se}, and
\nuclide[94]{Kr} in the ternary fission of \nuclide[252]{Cf}. These products
appear together with the clusters having mass numbers of --. The
results show that the yield of a heavy cluster such as \nuclide[68-70]{Ni}
would be followed by a product of -- with a large probability as
observed in the experimental data obtained with the FOBOS spectrometer at the
Joint Institute for Nuclear Research. The third product is not observed. The
landscape of the potential energy surface shows that the configuration of the
Ni + Ca + Sn decay channel is lower about 12 MeV than that of the Ca + Ni + Sn
channel. This leads to the fact, that the yield of Ni and Sn is large. The
analysis on the dependence of the velocity of the middle fragment on mass
numbers of the outer products leads to the conclusion that, in the collinear
tripartition channel of \nuclide[252]{Cf}, the middle cluster has a very small
velocity, which does not allow it to be found in experiments.Comment: 11 pages, 9 figure
2-n-Butyl-6-chloro-1-(2,4-dimethylphenylsulfonyl)-1H-benzimidazole–2-n-butyl-5-chloro-1-(2,4-dimethylphenylsulfonyl)-1H-benzimidazole (0.759/0.241)
The title compound, 0.759C19H21ClN2O2S·0.241C19H21ClN2O2S, was synthesized by arylsulfonylation of 2-n-butyl-5-chloro-1H-benzimidazole in the presence of triethylamine. The crystal structure is composed of two molecules, 2-n-butyl-6-chloro-1-(2,4-dimethylphenylsulfonyl)-1H-benzimidazole and 1-(2,4-dimethylphenylsulfonyl)-2-n-butyl-5-chloro-1H-benzimidazole, in the refined ratio of 0.759 (4):0.241 (4) disordered at the same position in the unit cell. The molecule has three essentially planar fragments viz. benzimidazole, dimethylbenzene and n-butyl (r.m.s. deviations of 0.009, 0.024 and 0.003 Å, respectively). The angle between the benzimidazole and dimethylbenzene fragments is 86.0 (1)°. In the crystal, pairs of intermolecular C—H⋯π interactions form centrosymmetrical dimers, which are linked by weak intermolecular C—H⋯O hydrogen bonds
Collinear cluster tripartition as sequential binary fission in the U(n,f) reaction
The mechanism leading to the formation of the observed products of the
collinear cluster tripartition is carried out within the framework of the model
based on the dinuclear system concept. The yield of fission products is
calculated using the statistical model based on the driving potentials for the
fissionable system. The minima of potential energy of the decaying system
correspond to the charge numbers of the products which are produced with large
probabilities in the sequential fission (partial case of the collinear cluster
tripartition) of the compound nucleus. The realization of this mechanism
supposes the asymmetric fission channel as the first stage of sequential
mechanism. It is shown that only the use of the driving potential calculated by
the binding energies with the shell correction allows us to explain the yield
of the true ternary fission products. The theoretical model is applied to
research collinear cluster tripartition in the reaction U(n,f). Calculations showed that in the first stage of this fission reaction,
the isotopes Ge and Nd are formed with relatively large
probabilities and in the second stage of sequential fission of the isotope Nd
mainly Ni and Ge are formed. This is in agreement with the yield of the isotope
Ni which is observed as the product of the collinear cluster
tripartition in the experiment.Comment: 20 pages, 9 figure
Pre-scission configuration of the tri-nuclear system at spontaneous ternary fission of
The potential energy surface for the pre-scission configurations of tri-nuclear systems formed in the spontaneous ternary fission of 252Cf is calculated. The fission channel 70Ni + 50Ca + 132Sn is chosen as one of the more probable channels of true ternary fission of 252Cf . A study of the collinear arrangement of the reaction products for true ternary fission is the aim of this work. The results are presented as a function of the relative distance R12 between the centres of mass of 70Ni and 132Sn and the distance from the centre of mass of 50Ca , which is perpendicular to R12. The results show that only for a particular range of the R12 values the collinear tripartion of the fissioning nucleus occurs
N-(5-Benzylsulfanyl-1,3,4-thiadiazol-2-yl)-2-(piperidin-1-yl)acetamide
The title compound, C16H20N4OS2, was synthesized by the reaction of 2-benzylsulfanyl-5-chloroacetamido-1,3,4-thiadiazole and piperidine in a 1:2 ratio. The planes of the acetamide and 1,3,4-thiadiazole units are twisted by 10.8 (4)°. The thiadiazole S atom and the acetamide O atom are syn-oriented due to a hypervalent S...O interaction of 2.628 (4) Å. In the crystal, molecules form centrosymmetric dimers via N—H...N hydrogen bonds. These dimers are further connected by C—H...O interactions into (100) layers