Knock out - a missing C1s line in the photoelectron spectrum of aqueous chloral hydrate : Core electron spectroscopy of chloral hydrate, trichloroethanol and ethanol in aqueous solution and gas phase

Abstract: Chloral hydrate Cl3C-C(OH)2H in aqueous solution has been studied by photoelectron spectroscopy using synchrotron radiation. The expected separation between the two carbon 1s lines due to different chemical environments could not be observed in the aqueous solution, but was clearly seen in following gas phase measurements. NMR measurements excluded sample damage in the aqueous solution and support the image of coincidence of the two carbon lines. The coincidence of the two lines is discussed in terms of experimental resolution and change in chemical shift in the aqueous phase. The observations are further compared to measurements of trichloroethanol and ethanol, which both exhibit the same characteristic C-C bond and at least one hydroxyl group. The present data showed no clear evidence of change in chemical shift in aqueous solution as compared to the gas phase, but such an effect might not be completely excluded. The liquid measurements were performed using a liquid micro-jet, a recently developed technique for accessing volatile liquids in a high vacuum environment as required for photoelectron spectroscopy. The set-up is described in detail. During the present project, I was involved into planning and performing experiments, sample preparation, data analysis and discussion.