STRUCTURE, DYNAMICS, AND ELECTRONIC-SPECTRUM OF N,N'-DIETHYL-P-NITROANILINE AT WATER INTERFACES - A MOLECULAR-DYNAMICS STUDY

The adsorption of N,N'-diethyl-p-nitroaniline (DEPNA)--a common chromo phore probe of liquid polarity--at the water liquid/vapor interface an d at the water/1,2-dichloroethane (DCE) interface is studied using mol ecular dynamics computer simulations. The adsorption energetics, orien tation, and reorientation dynamics are examined. The electronic absorp tion line shapes at the two interfaces, in bulk DCE, and in bulk water are calculated and are found to be in reasonable agreement with exper imental results. Including many-body polarizable liquid potentials in the calculations at the water/DCE interface is found to improve the re sults. The role of surface roughness is examined by repeating the calc ulations for an artificially smooth water/DCE interface.