Título: | LASER INDUCED DESORPTION IN INSULIN, CARBON AND ALKALI HALIDES | |||||||
Autor: |
FRANCISCO ALBERTO FERNANDEZ LIMA |
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Colaborador(es): |
ENIO FROTA DA SILVEIRA - Orientador EDWIN PEDRERO GONZALES - Coorientador |
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Catalogação: | 12/JUL/2006 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | |||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=8666&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=8666&idi=2 [fr] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=8666&idi=3 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.8666 | |||||||
Resumo: | ||||||||
Ion desorption induced by ultraviolet laser radiation
pulses was studied in
surfaces in vacuum. The ion desorption from three
different solids was analyzed:
insulin, carbon (amorphous and graphite) and polycrystals
of alkali halides. The
main processes involved in the laser-solid and laser-vapor
interactions, as well as
in the plasma evolution, were well described by a thermal
model and by the
simulation of the time-of-flight spectra for the first
moments of the plasma
expansion to vacuum. A new method to determine the initial
velocity and the
beginning of the free expansion regime as a function of
the laser intensity was
proposed for LDI (Laser Desorption Ionization) and MALDI
(Matrix Assisted
Laser Desorption Ionization). Considering the complexity
of the dynamical
treatment of the expansion of the laser-generated plasma,
an analysis by using
several combinations of irradiated solids was performed.
It was established that
the desorption process is characterized by two main
mechanisms: i) the
atomization followed by recombination of the target
elements in clusters and ii)
the emission of preformed clusters of the target material.
The most stable
geometric structures of the measured species were
characterized using Density
Functional Theory (DFT) and classified taxonomically as a
function of their
internal total energy (D-plot method); the influence of
the structure`s stability on
the relative mass abundances was also determined.
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