Calculation of electric multipole moment integrals with the different screening parameters via the Fourier transform method

2011 ◽  
Vol 112 (2) ◽  
pp. 414-425 ◽  
Author(s):  
N. Yükçü ◽  
İ. Şenlik ◽  
E. Öztekin
Keyword(s):  
Fourier Transform ◽  
Multipole Moment ◽  
Transform Method ◽  
Fourier Transform Method ◽  
The Fourier Transform ◽  
Electric Multipole Moment

Fast analytical evaluation of intermolecular electrostatic interaction energies using the pseudoatom representation of the electron density. II. The Fourier transform method

2019 ◽  
Vol 75 (3) ◽  
pp. 448-464 ◽  
Author(s):  
Daniel Nguyen ◽  
Anatoliy Volkov
Keyword(s):  
Fourier Transform ◽  
Electrostatic Interaction ◽  
Multipole Moment ◽  
Floating Point ◽  
Interaction Energies ◽  
Transform Method ◽  
Fourier Transform Method ◽  
The Fourier Transform ◽  
Coulomb Integrals ◽  
Löwdin Α Function

The Fourier transform method for analytical determination of the two-center Coulomb integrals needed for evaluation of the electrostatic interaction energies between pseudoatom-based charge distributions is presented, and its Fortran-based implementation using the 128-bit floating-point arithmetic in theXDPROPmodule of theXDsoftware is described. In combination with mathematical libraries included in the Lahey/Fujitsu LF64 Linux compiler, the new implementation outperforms the previously reported Löwdin α-function technique [Nguyenet al.(2018).Acta Cryst.A74, 524–536] in terms of precision of the determined individual Coulomb integrals regardless of whether the latter uses the 64-, 80- or 128-bit precision floating-point format, all the while being only marginally slower. When the Löwdin α-function or Fourier transform method is combined with a multipole moment approximation for large interatomic separations (such a hybrid scheme is called the analytical exact potential and multipole moment method, aEP/MM) the resulting electrostatic interaction energies are evaluated with a precision of ≤5 × 10−5 kJ mol−1for the current set of benchmark systems composed of H, C, N and O atoms and ranging in size from water–water to dodecapeptide–dodecapeptide dimers. Using a 2012 4.0 GHz AMD FX-8350 computer processor, the two recommended aEP/MM implementations, the 80-bit precision Löwdin α-function and 128-bit precision Fourier transform methods, evaluate the total electrostatic interaction energy between two 225-atom monomers of the benchmark dodecapeptide molecule in 6.0 and 7.9 s, respectively, versus 3.1 s for the previously reported 64-bit Löwdin α-function approach.

The interpretation of x-ray rocking curves by the Fourier transform method

1997 ◽  
Vol 30 (24) ◽  
pp. 3296-3300 ◽  
Author(s):  
M Li ◽  
M O Möller ◽  
H R Reß ◽  
W Faschinger ◽  
G Landwehr
Keyword(s):  
Fourier Transform ◽  
Transform Method ◽  
Fourier Transform Method ◽  
X Ray ◽  
The Fourier Transform

Poisson’s integral formula via heat kernels

Analysis ◽  
2019 ◽  
Vol 39 (2) ◽  
pp. 59-64
Author(s):  
Yoichi Miyazaki
Keyword(s):  
Fourier Transform ◽  
Heat Kernel ◽  
Half Space ◽  
Unbounded Domain ◽  
Harmonic Functions ◽  
Integral Formula ◽  
Heat Kernels ◽  
Transform Method ◽  
Fourier Transform Method ◽  
The Fourier Transform

Abstract We give another proof of Poisson’s integral formula for harmonic functions in a ball or a half space by using heat kernels with Green’s formula. We wish to emphasize that this method works well even for a half space, which is an unbounded domain; the functions involved are integrable, since the heat kernel decays rapidly. This method needs no trick such as the subordination identity, which is indispensable when applying the Fourier transform method for a half space.

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