Comparative analysis of (p,d), (d,t) and (3He, α) reactions on13C nucleus

The angular distributions of the (p, d), (d, t) and(³He, ) reactions on¹³C have been analysed within the framework of DWBA in which additional information on nuclear vertex constants was introduced. Although all these reactions seem to be similar single nucleon transfer, their mechanism is shown to be quite different and so is the information extracted thereof. While from the (p, d) reactions spectroscopic factors may be extracted unambiguously, from the (d, t) reactions it is possible to obtain directly the values of vertex constants only, which in turn are consistent with those determined by extrapolation of the experimental cross sections of the (p, d) reactions to the pole.In the case of (³He, ) reactions, however, the analysis indicates inadequacy of the DWBA concerning the calculations of central partial amplitudes. For a more reliable extraction of structural information, besides the correct normalization of peripheral amplitudes, a contribution of more complex mechanisms must be taken into account.     

Reaction of γ-nitroketones and methyl 4-nitrobutanoates with formaldehyde and primary amines

5-Nitropentan-2-one reacts with methylamine and formaldehyde according to the Mannich reaction pattern to give 5-hexahydropyrimidinylcarbonyl-substituted 1-nitro-3,7-diazabicyclo[3.3.1]nonane in one experimental stage. When methyl 3-R-4-nitrobutanoates are used, the reaction stops after the formation of substituted 5-nitrohexahydropyrimidines in 40–98% yields. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1687–1693, July, 2005.     

On Harmonic Continuation of Differentiable Functions Defined on Part of the Boundary

We establish an explicit formula for reconstruction of a harmonic function in a domain from its values and the values of its normal derivative on part of the boundary; i.e., we give an explicit solution to the Cauchy problem for the Laplace equation.     

Asymptotic normalization coefficients (nuclear vertex constants) for p + 7Be → 8B and the direct 7Be(p, γ)8B astrophysical S factors at solar energies

A new analysis of the precise experimental astrophysical S factors for the direct-capture reaction ⁷Be(p, γ)⁸B [A.J. Junghans et al., Phys. Rev. C 68, 065803 (2003) and L.T. Baby et al., Phys. Rev. C 67, 065805 (2003)] is carried out on the basis of a modified two-body potential approach in which the direct astrophysical S factor, S ₁₇(E), is expressed in terms of the asymptotic normalization constants for p + ⁷Be → ⁸B and two additional conditions are involved to verify the peripheral character of the reaction under consideration. The Woods-Saxon potential form is used for the bound-(p + ⁷Be)-state wave function and for p ⁷Be-scattering wave function. New estimates are obtained for the “indirectly measured” values of the asymptotic normalization constants (the nuclear vertex constants) for the p + ⁷Be → ⁸B and S ₁₇(E) at E ≤ 115 keV, including E = 0. These values of S ₁₇(E) and asymptotic normalization constants have been used for obtaining the indirectly measured values of the s-wave average scattering length and the p-wave effective-range parameters for p ⁷Be scattering. The text was submitted by the authors in English.     

Nuclear asymptotic normalization coefficients for <Superscript>14</Superscript>N → <Superscript>13</Superscript>C + <Emphasis Type="Italic">p</Emphasis> configurations and astrophysical <Emphasis Type="Italic">S</Emphasis> factor for radiative proton capture

Empirical values of the asymptotic normalization coefficient for proton bound states in the ¹⁴N nucleus for the first five levels were obtained from an analysis of the experimental differential cross sections known from our measurements and from the literature for the reaction ¹³C(³He, d)¹⁴N in the projectile-energy range between about 15 and 40 MeV. The values obtained in this way were used to calculate the astrophysical S factors for the reaction ¹³C(p, γ)¹⁴N in the case of the population of the first five levels of the 14N nucleus. The calculations were based on the R-matrix approach. The calculated values are in good agreement with the experimental astrophysical S factor at energies below 1 MeV.     

Asymptotic Normalization Coefficients (Nuclear Vertex Constants), Three-Body Asymptotic Normalization Functions (On-Shell Vertex Functions) and Nuclear Astrophysics

In the present review work, the main methods of the determination of asymptotic normalization coefficients (or respective nuclear vertex constants) for the A + x → B channel and of threebody asymptotic normalization functions (or respective on-shell vertex functions) for the A + b + c → B channel are briefly discussed. The main attention is paid both to the use of the specific asymptotic normalization coefficients and three-body asymptotic normalization functions as a source of getting the valuable information about the pair (nucleon–nucleon, nucleon–cluster and cluster–cluster) nuclear interactions and to their application for the specific direct nuclear-astrophysical radiative capture and peripheral transfer reactions at low energies.     

Extrapolation of astrophysical <Emphasis Type="Italic">S</Emphasis> factors for the reaction <Superscript>14</Superscript>N((<Emphasis Type="Italic">p, γ</Emphasis>) <Superscript>15</Superscript>O to near-zero energies

The astrophysical S factors for the radiative-capture reaction ¹⁴N(p, γ)¹⁵O in the region of ultralow energies were calculated on the basis of the R-matrix approach. The values of the radiative and protonic widths were fitted to new experimental data. The contribution of direct radiative capture to bound states of the ¹⁵O nucleus was determined with the aid of asymptotic normalization coefficients, whose values were refined in the present study on the basis of the results obtained from an analysis of the reaction ¹⁴N(³He, d)¹⁵O at three different energies of incident helium ions. A value of S(0) = 1.79 ± 0.31 keV b was obtained for the total astrophysical S factor, and the reaction rate was determined for the process ¹⁴N(p, γ)¹⁵O.     

Channel coupling and exchange of an alpha-particle cluster in deuteron scattering on 6Li nuclei

Existing experimental data on elastic and inelastic deuteron scattering on ⁶Li nuclei in the energy range from 8 to 50 MeV were analyzed within the approach of coupled reaction channels. The coupling of elastic scattering and inelastic scattering accompanied by the transition to the 3⁺ state at E _x = 2.186 MeV and the mechanism involving the exchange of an alpha-particle cluster were taken into account in respective calculations. The phenomenological potentials obtained from the present analysis describe well experimental angular distributions at all energies and in full angular ranges. The depths of the real and imaginary parts of the potentials in question depend smoothly on energy at fixed values of the remaining parameters. The energy dependence of relevant volume integrals agrees well with similar data for the p + ⁶Li, ?? + ⁶Li, and ¹²C + ¹²C systems and with the predictions of a microscopic theory.     

One-step synthesis of substituted 3,5-dinitropiperidines and 1,5-dinitro-3,7-diazabicyclo[3.3.1]nonanes from 1,3-dinitropropanes

1,5-Dinitro-3,7-diazabicyclo[3.3.1]nonane derivatives were synthesized in up to 83%yields by the Mannich reaction of 1,3-dinitropropanes with excess formaldehyde and primary amines. In some cases, for instance, when 2,2-dimethyl-1,3-dinitropropane and benzylamine or monoethanolamine are used, the reaction occurs with low yields or stops at the step of formation of 3,5-dinitropiperidines. The influence of the structure of the starting compounds and reaction conditions on the yields of 1,5-dinitro-3,7-diazabicyclo[3.3.1]nonanes and 3,5-dinitropiperidines was studied.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 405–411, February, 2005.     

Spectroscopic factors and nuclear vertex constants from the (p,d) reactions on7Li,9Be and13C nuclei

The angular distributions of the (p, d) reactions on the⁷Li,⁹Be and¹³C nuclei have been analysed within the framework of the new approach to the extraction of the structural information from the direct nuclear reactions. In this method the additional physical information on the nuclear vertex constants is introduced into the standard DWBA calculations, which makes possible to eliminate the strong dependence of the spectroscopic factors on the geometry of bound state potentials. The possibility of the model — independent determination of the spectroscopic factors — is discussed.The authors wish to express their gratitude to I. Borbely for assistance in the calculations by the method of subtraction of singularities.