Second harmonic generation measurements of molecular orientation and coadsorption at the interface between two immiscible electrolyte solutions

✍ Scribed by Daniel A. Higgins; Roberta R. Naujok; Robert M. Corn

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 555 KB
• Volume: 213
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(93)89146-9

✦ Synopsis

Resonant optical second harmonic generation (SHG) is obtained from monolayers of 4-n-octyloxybenzoic acid (OBA) and noctyl-4-hydroxybenzoate (OHB) adsorbed at the water/ 1,2dichloroethane interface. The polarization dependence of the SHG from pure monolayers of OBA and OHB indicates that the molecular axis of the OBA molecules is tilted 6" closer to the surface normal than that of the OHB molecules. The SHG from a series of mixed monolayers of OBA and OHB exhibits interference effects that demonstrate that the dipole moments of the coadsorbed molecules are oriented in opposite directions at the interface.