scholarly journals Tan's adiabatic sweep theorem from the variational theorem for the scattering length

2021 ◽  
Vol 104 (4) ◽  
Author(s):  
Alexander Yu. Cherny
Keyword(s):  
Scattering Length ◽  
Variational Theorem

scholarly journals THEORY OF COMPLEX SCATTERING LENGTHS

2001 ◽  
Vol 15 (03) ◽  
pp. 105-109
Author(s):  
M. S. HUSSEIN
Keyword(s):  
Scattering Length ◽  
Effective Range ◽  
Low Energies ◽  
T Matrix ◽  
Scattering Lengths ◽  
New Equation ◽  
Molecule Interaction ◽  
Complex Atom

We derive a generalized Low equation for the T-matrix appropriate for complex atom–molecule interaction. The properties of this new equation at very low energies are studied and the complex scattering length and effective range are derived.

scholarly journals Next-to-next-to-leading-orderϵexpansion for a Fermi gas at infinite scattering length

2007 ◽  
Vol 75 (4) ◽  
Author(s):  
Peter Arnold ◽  
Joaquín E. Drut ◽  
Dam Thanh Son
Keyword(s):  
Scattering Length ◽  
Fermi Gas

A new time-of-flight small-angle scattering instrument at the Helmholtz-Zentrum Berlin: V16/VSANS

2014 ◽  
Vol 47 (1) ◽  
pp. 237-244 ◽  
Author(s):  
Karsten Vogtt ◽  
Miriam Siebenbürger ◽  
Daniel Clemens ◽  
Christian Rabe ◽  
Peter Lindner ◽  
...  
Keyword(s):  
Momentum Transfer ◽  
Small Angle ◽  
Soft Matter ◽  
Scattering Length ◽  
Time Of Flight ◽  
Small Angle Scattering ◽  
Neutron Guide ◽  
Macromolecular Assemblies ◽  
Angle Scattering ◽  
The Individual

Small-angle scattering methods have become routine techniques for the structural characterization of macromolecules and macromolecular assemblies like polymers, (block) copolymers or micelles in the spatial range from a few to hundreds of nanometres. Neutrons are valuable scattering probes, because they offer freedom with respect to scattering length density contrast and isotopic labelling of samples. In order to gain maximum benefit from the allotted experiment time, the instrumental setup must be optimized in terms of statistics of scattered intensity, resolution and accessible range in momentum transferQ. The new small-angle neutron scattering instrument V16/VSANS at the Helmholtz-Zentrum in Berlin, Germany, augments neutron guide collimation and pinhole optics with time-of-flight data recording and flexible chopper configuration. Thus, the availableQrange and the respective instrumental resolution in the intermediate and high momentum transfer regions can be adjusted and balanced to the individual experimental requirements. This renders V16/VSANS a flexible and versatile instrument for soft-matter research.

Model-independent determination of the surface scattering-length-density profile from specular reflectivity data

1992 ◽  
Vol 25 (2) ◽  
pp. 129-145 ◽  
Author(s):  
J. S. Pedersen
Keyword(s):  
Density Profile ◽  
Fourier Transformation ◽  
Scattering Length ◽  
Simulated Data ◽  
Limited Range ◽  
Square Root ◽  
Scattering Length Density ◽  
Angle Scattering ◽  
Specular Reflectivity ◽  
Reflectivity Data

An approach for analysing neutron and X-ray specular reflectivity data from stratified media having variation in the scattering-length density near the surface is described. The method has its origin in small-angle scattering and it is composed of two steps: (i) indirect Fourier transformation [Glatter (1977). J. Appl. Cryst. 10, 415–421] giving the profile correlation function p(z) of the derivative dρ/dz of the scattering-length density; (ii) square-root deconvolution [Glatter (1981). J. Appl. Cryst. 14, 101–108] giving dρ/dz and ρ, the scattering-length-density profile. The only requirement for applying the method is that the scattering-length density varies only in a limited range. In nearly all cases the approach does not require any knowledge of the chemical composition of the surface layer and consequently incorporates a certain degree of objectivity. The method gives the smoothest profile which agrees with the experimental reflectivity data. The method is tested on simulated reflectivity data for a series of different surface profiles and subsequently used for analysing experimental data on fluorocarbon amphiphiles in water and salt solutions. The tests on simulated data show that the indirect Fourier transformation gives correlation functions agreeing very well with the corresponding functions of the original profiles. It is further demonstrated that the square-root deconvolution gives reliable results for the scattering-length-density profiles.

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