Selectivity in fragmentation of N-methylacetamide after resonant K-shell excitation
2014 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 29, 15231-15240 p.Article in journal (Refereed) Published
The fragmentation pattern of the peptide model system, N-methylacetamide, is investigated using ion time-of-flight (TOF) spectroscopy after resonant K-shell excitation. Corresponding near-edge X-ray absorption fine structure (NEXAFS) spectra recorded at high resolution at the C1s, N1s and O1s edges are presented. Analysis of the ion TOF data reveals a multitude of fragmentation channels and dissociation pathways. Comparison between the excitation of six different resonances in the vicinity of the C1s, N1s and O1s edges suggests evidence for site-selective bond breaking. In particular the breaking of the peptide bond and the N-C-alpha bond show a clear correlation with resonant excitation at the N1s edge. Also, stronger tendencies towards site-selective bond breaking are found for the generation of single ions compared with ion pairs. Analysis of angular distributions of ions from breakage of the peptide bond yields a fragmentation time of <400 fs.
Place, publisher, year, edition, pages
2014. Vol. 16, no 29, 15231-15240 p.
IdentifiersURN: urn:nbn:se:uu:diva-230538DOI: 10.1039/c4cp01067aISI: 000339173700022OAI: oai:DiVA.org:uu-230538DiVA: diva2:740898