Probing the role of PO stretching mode enhancement in nerve-agent sensors: Simulation of the adsorption of diisopropylfluorophosphate on the model MgO and CaO surfaces

The interactions of diisopropylfluorophosphate (DFP) with model MgO and CaO surfaces have been investigated using density functional (DFT) and Møller–Plesset second order perturbation techniques. The geometries were fully optimized at the DFT level. The calculated interaction energies and the corresponding thermodynamic properties show that DFP is physisorbed on these two model oxide surfaces and adsorption on the MgO surface is stronger. Analyses of the calculated IR and Raman spectra point to the enhancement of the PO stretching mode with respect to the isolated DFP and this property could be used to detect nerve-agents using surface-enhanced Raman spectroscopy.