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Inversion of simulated positron annihilation lifetime spectra by moving boundary subspaces
Author(s) -
Viterbo V. C.,
Neves J. L.,
Braga J. P.,
Monteiro R. P. G.,
De Magalhães W. F.
Publication year - 2003
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10658
Subject(s) - singular value decomposition , annihilation , linear subspace , spectral line , physics , noise (video) , inversion (geology) , positron annihilation , dirac delta function , filter (signal processing) , function (biology) , positron , computational physics , quantum mechanics , statistical physics , atomic physics , algorithm , mathematics , electron , geometry , computer science , artificial intelligence , evolutionary biology , paleontology , structural basin , image (mathematics) , biology , computer vision
The retrieval of the density function for the positron annihilation lifetime spectrum is obtained from simulated data using the damped singular value decomposition. Two filters factors were discussed, for noise and noiseless data, and under the L curve criterion. The obtained density function is exact in the absence of noise. When noise is considered, the predicted peaks are at positions λ 1 = 0.4167 ns −1 , λ 2 = 2.418 ns −1 , whereas the exact results are λ 1 = 0.5250 ns −1 and λ 2 = 2.538 ns −1 . The computed areas for these peaks are also in fair agreement when compared with the theoretical results. In this case, a filter factor that takes into account all the singular values was found appropriate. The current study shows that the damped singular value decomposition approach can be used to invert real laboratory data. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 95: 97–102, 2003