Palavras-chave
Fotoionização
Espectroscopia de fotoelétrons
Espectroscopia de elétrons Auger
Espectroscopia de fotoelétrons de limiar (TPES)
PEPICO
TPEPICO
PEPECO
TOF-PEPECO
Radiação síncrotron
Métricas
Como Citar
Resumo
A determinação rigorosa de energias de ionização é fundamental para a compreensão das propriedades eletrônicas e estruturais de átomos e moléculas. O presente texto corresponde a uma revisão, comparando as principais técnicas espectroscópicas experimentais empregadas nessa determinação, destacando seus princípios, requisitos instrumentais, aplicações e limitações. Inicialmente, são discutidas as espectroscopias de fotoelétrons na região do ultravioleta (UPS) e de raios X (XPS), empregadas na obtenção de energias de ionização simples. Em seguida, apresenta-se a espectroscopia de fotoelétrons de limiar (TPES), que oferece elevada resolução e versatilidade na variação da energia de fótons. São apresentadas ainda as técnicas de coincidência PEPICO, TPEPICO, PEPECO e TOF-PEPECO, capazes de relacionar a detecção de fotoelétrons e fotoíons, permitindo a investigação detalhada de processos de fragmentação e de ionização múltipla. Essas abordagens fornecem informações complementares sobre os estados eletrônicos finais e os mecanismos de dissociação, ampliando a compreensão da dinâmica de ionização em sistemas gasosos e moleculares complexos. Conclui-se que a escolha da técnica mais adequada depende da natureza do sistema estudado, das condições experimentais disponíveis e do tipo de informação espectroscópica buscada.
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