Calcium oxalate monohydrate is found as a by-product of environmental damage to stonework of importance in preserving cultural heritage. XPS (X-ray Photoelectron Spectroscopy) was here used to characterize the standard compound, calcium oxalate monohydrate, RPE, chemically synthesized as provided by Carlo Erba Reagents - Cod. 434004. Degradation occurred during analysis and this is described. Repeat XPS acquisitions have allowed us to monitor the spectral changes of calcium oxalate during the whole process of analysis: its degradation was rationalized by considering the effect of x-ray power; UHV exposure; and thermal effects suffered by the powdered sample after its insertion into the spectrometer and, particularly, during spectra acquisition. Measurement of degradation with time enabled extrapolation to yield the primary composition. It was found that samples will completely dehydrate in ultra high vacuum, UHV. Although dehydrated samples are then stable in UHV, during XPS acquisitions degradation of calcium oxalate occurs and continues in UHV, even in the absence of x-ray exposure. © 2015 American Vacuum Society.

Comparative Spectra Illustrating Degradation of CaC2O4*H2O During XPS analysis

SALVI, Anna Maria;LANGERAME, Fausto;CARBONE, MARIA ELVIRA EGIDIA;CIRIELLO, Rosanna
2015-01-01

Abstract

Calcium oxalate monohydrate is found as a by-product of environmental damage to stonework of importance in preserving cultural heritage. XPS (X-ray Photoelectron Spectroscopy) was here used to characterize the standard compound, calcium oxalate monohydrate, RPE, chemically synthesized as provided by Carlo Erba Reagents - Cod. 434004. Degradation occurred during analysis and this is described. Repeat XPS acquisitions have allowed us to monitor the spectral changes of calcium oxalate during the whole process of analysis: its degradation was rationalized by considering the effect of x-ray power; UHV exposure; and thermal effects suffered by the powdered sample after its insertion into the spectrometer and, particularly, during spectra acquisition. Measurement of degradation with time enabled extrapolation to yield the primary composition. It was found that samples will completely dehydrate in ultra high vacuum, UHV. Although dehydrated samples are then stable in UHV, during XPS acquisitions degradation of calcium oxalate occurs and continues in UHV, even in the absence of x-ray exposure. © 2015 American Vacuum Society.
2015
File in questo prodotto:
File Dimensione Formato  
Surface Science Spectra 2015.pdf

non disponibili

Tipologia: Pdf editoriale
Licenza: DRM non definito
Dimensione 1.79 MB
Formato Adobe PDF
1.79 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11563/111703
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 24
  • ???jsp.display-item.citation.isi??? 24
social impact