Sandhyarani, N. and Skanth, G. and Sheela, B. and Yegnaraman, V. and Pradeep, T. (1999) A Combined Surface-Enhanced Raman–X-Ray Photoelectron Spectroscopic Study of 2-mercaptobenzothiazole Monolayers on Polycrystalline Au and Ag Films. Journal of Colloid and Interface Science, 209. pp. 154-161. ISSN 0021-9797

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Abstract

The monolayers of 2-mercaptobenzothiazole (MBT) on polycrystalline Au and Ag films have been studied by surface-enhanced Raman (SERS) and X-ray photoelectron (XPS) spectroscopies. Whereas MBT adsorbs with its molecular plane flat on Ag, its plane is perpendicular on Au. This difference in adsorbate geometry is manifested as differences in the intensities of certain vibrational peaks in the Raman spectra. Ab initio molecular orbital (MO) calculations suggest that MBT adsorbs on Au in the thione form and on Ag in the thiol form. The monolayers are stable up to a temperature of 473 K, much higher than most of the self-assembled monolayers (SAMs) studied so far. The adsorption geometry does not undergo any significant change when the monolayers are heated, although minor changes are observed in the SER spectra of the Ag monolayer. Raman intensities of all the bands increase with heating, and the enhanced intensity is preserved even after cooling. This is attributed to monolayer-induced coalescence of gold islands leading to the formation of an extended self-assembly. XPS studies confirm chemisorption, although structural details are not manifested.

Item Type:	Article
Uncontrolled Keywords:	self-assembled monolayers; surface-enhanced Raman spectroscopy; ab initio MO calculations; X-ray photoelectron spectroscopy
Subjects:	Electrodics and Electrocatalysis
Divisions:	UNSPECIFIED
Depositing User:	ttbdar CECRI
Date Deposited:	08 May 2012 06:11
Last Modified:	08 May 2012 06:11
URI:	http://cecri.csircentral.net/id/eprint/1269

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