TY - JOUR
T1 - Atomic modifications by synchrotron radiation at the calcite-ethanol interface
AU - Sanchez Pasarin, Ivan Jesus
AU - Bovet, N.
AU - Glyvradal, Magni
AU - Nielsen, Martin Meedom
AU - Feidenhans'l, Robert Krarup
AU - Stipp, Susan Louise Svane
PY - 2012/7
Y1 - 2012/7
N2 - This article reports on studies of the chemical alterations induced by synchrotron radiation at the calcite-ethanol interface, a simple model system for interfaces between minerals and more complex organic molecules containing OH groups. A combination of X-ray reflectivity and X-ray photoelectron spectroscopy of natural calcite, cleaved in distilled ethanol to obtain new clean interfaces, indicated that, during a 5 h period, the two top atomic layers of calcite, CaCO 3, transform into calcium oxide, CaO, by releasing CO 2. Also, the occupation of the first ordered layer of ethanol attached to calcite by hydrogen bonds almost doubles. Comparison between radiated and non-radiated areas of the same samples demonstrate that these effects are induced only by radiation and not caused by aging. These observations contribute to establishing a time limit for synchrotron experiments involving fluid-mineral interfaces where the polar OH group, as present in ethanol, plays a key role in their molecular structure and bonding. Also, the chemical evolution observed in the interface provides new insight into the behavior of some complex organic molecules involved in biomineralization processes.
AB - This article reports on studies of the chemical alterations induced by synchrotron radiation at the calcite-ethanol interface, a simple model system for interfaces between minerals and more complex organic molecules containing OH groups. A combination of X-ray reflectivity and X-ray photoelectron spectroscopy of natural calcite, cleaved in distilled ethanol to obtain new clean interfaces, indicated that, during a 5 h period, the two top atomic layers of calcite, CaCO 3, transform into calcium oxide, CaO, by releasing CO 2. Also, the occupation of the first ordered layer of ethanol attached to calcite by hydrogen bonds almost doubles. Comparison between radiated and non-radiated areas of the same samples demonstrate that these effects are induced only by radiation and not caused by aging. These observations contribute to establishing a time limit for synchrotron experiments involving fluid-mineral interfaces where the polar OH group, as present in ethanol, plays a key role in their molecular structure and bonding. Also, the chemical evolution observed in the interface provides new insight into the behavior of some complex organic molecules involved in biomineralization processes.
U2 - 10.1107/S0909049512021504
DO - 10.1107/S0909049512021504
M3 - Journal article
SN - 0909-0495
VL - 19
SP - 530
EP - 535
JO - Journal of Synchrotron Radiation
JF - Journal of Synchrotron Radiation
IS - Part 4
ER -