Direct observation of a self-assembled monolayer of heptyl xanthate at the germanium/water interface: a polarized FTIR study

Attenuated Total Reflection - Infrared Spectroscopy Applied to the Study of Mineral - Aqueous Electrolyte Solution Interfaces: A General Overview and a Case Study

“…Either the surface of the crystal is used as received, as ZnSe on which sodium dodecyl sulfate (Gao and Chorover, 2010) or Ge on which heptyl xanthate (Larsson et al, 2004) formed a monolayer, or the surface was chemically modified and is different from the bulk. Thus, Asay and Kim (2005) studied the adsorption of water molecules on the native layer of silica present on a silicium ATR crystal, or Wang et al (2006) studied the adsorption of hexane and ethylbenzene from the vapor phase on a layer of zeolite grown directly on the surface of a silicium ATR crystal.…”

In situ ATR–FTIR studies on the competitive adsorption of arsenate and phosphate on ferrihydrite

“…To the best of our knowledge, this is the first report monitoring both arsenate and phosphate species during competitive adsorption onto iron oxide using this in situ method, which is a powerful tool to study adsorption onto and desorption from thin mineral layers [25][26][27][28][29][30]. The aim was to gain new insight into the stability of adsorbed arsenate and phosphate and simultaneously get molecular information about the surface complexes formed and their stabilities.…”

n-Heptyl xanthate adsorption on a ZnS layer synthesized on germanium: An in situ attenuated total reflection IR study

“…They found that the equation derived to quantify the amount of adsorbed molecules also was useful to estimate the degree of monolayer coverage. In a recent publication we have used the relation between integrated absorbance and surface concentration to estimate the density of adsorbed n-heptyl xanthate on germanium [16]. It was shown by transmission measurements that the integrated absorbance between 2820 and 3000 cm −1 , as well as the peak absorbance of the asymmetric CH 2 stretch, both varied linearly with the bulk concentration of n-heptyl xanthate in D 2 O as solvent.…”

“…This was accomplished by recording polarized spectra of a thin layer of dodecane on the ZnS film, yielding a dichroic ratio of A s /A p ≈ 0.57, which we assume to be the ratio for isotropic alkyl chains. This assumption seems reasonable since a thin film of dodecane (refractive index 1.4) on a Ge crystal would imply a dichroic ratio of 0.56 in the three-layer model if the molecules were randomly orientated [15,16]. An organic film with refractive index of around 1.5 (the same as n-heptyl xanthate) would result in a theoretical A s /A p ratio of 0.63, as calculated using the same three-layer model.…”

“…Polarized IR-ATR allows determination of the orientation of adsorbed species through the ratio of the absorbance values caused by the incident electric field parallel and perpendicular to the crystal surface. A number of such studies, predominantly ex situ [12][13][14] but only very few in situ investigations [15][16][17], have appeared during the last few decades.…”