Restricted Radial Functions for Analysis of Molecular Form Factors

1980 ◽  
pp. 433-437
Author(s):  
C. Ceccarelli ◽  
R. F. Stewart
Keyword(s):  
Molecular Form ◽  
Form Factors ◽  
Radial Functions

Structural complexity of a polar perhydrotriphenylene inclusion compound brought to light by synchrotron radiation

2001 ◽  
Vol 57 (4) ◽  
pp. 579-590 ◽  
Author(s):  
Thomas Weber ◽  
Michael A. Estermann ◽  
Hans-Beat Bürgi
Keyword(s):  
Synchrotron Radiation ◽  
Diffuse Scattering ◽  
Molecular Form ◽  
Three Dimensional ◽  
Structural Complexity ◽  
Form Factors ◽  
Guest Molecules ◽  
Positional Disorder ◽  
Average Structure ◽  
Area Detector

The complex diffraction pattern of the heavily disordered co-crystals of perhydrotriphenylene and 1-(4-nitrophenyl)piperazine (5C18H30·C10H13N3O2) has been investigated with synchrotron radiation and an area detector. Five (almost) complete, three-dimensional data sets have been obtained from the tips and the centre of a needle-like crystal at room temperature and 120 K. They revealed a rich variety of features including one,- two- and three-dimensional diffuse scattering, as well as incommensurate satellites. At the centre and one tip of the crystal the symmetry appears to be orthorhombic, whereas at the other tip the symmetry of the satellites and of some of the diffuse scattering is clearly monoclinic, indicating that the crystal is not homogeneous. Most of the scattering could be assigned to R/S occupational disorder of the chiral host molecules, to positional disorder of the guest molecules or to local distortions of the average structure. Assignments are based on the disorder deduced from the average structure and the molecular form factors of host and guest molecules which show characteristic patterns in reciprocal space. Two smaller, orthorhombic twin fragments and an additional phase with hexagonal symmetry have also been found.

scholarly journals Molecular form factors in X-ray crystallography

1969 ◽  
Vol 25 (3) ◽  
pp. 444-450 ◽  
Author(s):  
P. P. M. Groenewegen ◽  
D. Feil
Keyword(s):  
Molecular Form ◽  
Form Factors ◽  
X Ray ◽  
X Ray Crystallography

Efficient evaluation of X-ray scattering integrals of Cartesian Gaussian-type functions

1986 ◽  
Vol 42 (4) ◽  
pp. 257-261 ◽  
Author(s):  
M. Barua ◽  
W. Weyrich
Keyword(s):  
Cross Sections ◽  
Wigner Distribution ◽  
Molecular Form ◽  
Form Factors ◽  
Distribution Functions ◽  
Gaussian Type ◽  
X Ray Scattering ◽  
Recurrence Algorithm ◽  
Scattering Cross Sections ◽  
Special Case

A general recurrence algorithm and explicit analytical results are given for scattering integrals with Cartesian Gaussian-type functions, in a form that is necessary for the evaluation of molecular form factors, Wigner distribution functions and Compton scattering cross sections. Overlap integrals are included as a special case.

Organic Syntheses During the Impact of a Comet with a Gaseous Planet

1997 ◽  
Vol 161 ◽  
pp. 189-195
Author(s):  
Cesare Guaita ◽  
Roberto Crippa ◽  
Federico Manzini
Keyword(s):  
Polymeric Material ◽  
Molecular Form ◽  
Parent Compound ◽  
Blue Filter ◽  
Organic Syntheses ◽  
The Impact

AbstractA large amount of CO has been detected above many SL9/Jupiter impacts. This gas was never detected before the collision. So, in our opinion, CO was released from a parent compound during the collision. We identify this compound as POM (polyoxymethylene), a formaldehyde (HCHO) polymer that, when suddenly heated, reformes monomeric HCHO. At temperatures higher than 1200°K HCHO cannot exist in molecular form and the most probable result of its decomposition is the formation of CO. At lower temperatures, HCHO can react with NH3 and/or HCN to form high UV-absorbing polymeric material. In our opinion, this kind of material has also to be taken in to account to explain the complex evolution of some SL9 impacts that we observed in CCD images taken with a blue filter.

THE STRUCTURE OF 6Li AND ITS COULOMB FORM FACTORS

1971 ◽  
Vol 32 (C5) ◽  
pp. C5b-269-C5b-270
Author(s):  
Kuniharu Kubodera
Keyword(s):  
Form Factors
Sign in / Sign up

Export Citation Format

Share Document