Accession Number:

ADA280958

Title:

Atomic Force Microscopy of the Electrochemical Nucleation and Growth of Molecular Crystals

Descriptive Note:

Technical rept. no. 1, 1 May 1993-30 Jun 1994

Corporate Author:

MINNESOTA UNIV MINNEAPOLIS DEPT OF CHEMICAL ENGINEERING AND MATERIALS SCIENCE

Personal Author(s):

• Ward, M. D.
• Hillier, A. C.

Report Date:

1994-06-23

Pagination or Media Count:

20.0

Abstract:

In situ atomic force microscopy reveals the morphology, surface topology, and growth and dissolution characteristics of microscopic single crystals of the low dimensional organic conductor tetrathiafulvaleneBr0.76, which are grown by electrocrystallization on a highly oriented pyrolytic graphite electrode in an atomic force microscope liquid cell. The growth modes, and the distribution and orientation of topographic features i.e., terraces, ledges, and kinks on specific crystal faces, as assigned by atomic force microscopy goniometry, can be correlated with the strength and direction of anisotropic solid state intermolecular bonding. The influence of substrate structure was evident during growth on the 011 face of tetrathiafulvalene Br0.76 crystals, which involves the formation of oriented self-similar triangular islands ranging from 200 A to 5000 A along a side. These nuclei eventually transform into rectangular rafts at larger length scales, where bulk intermolecular bonding interactions and surface energies dominate over nuclei- substrate interactions.

Descriptors:

• *MOLECULES
• *ELECTROCHEMISTRY
• *NUCLEATION
• *CRYSTAL GROWTH
• *MICROSCOPY
• *PYROLYTIC GRAPHITE
• FRACTALS
• CONDUCTIVITY
• SUBSTRATES
• CHEMICAL BONDS
• ELECTRODES
• GONIOMETERS
• SOLID STATE CHEMISTRY
• ORGANIC COMPOUNDS
• ANISOTROPY
• SURFACES
• TOPOGRAPHY
• CRYSTALLIZATION
• SINGLE CRYSTALS
• MORPHOLOGY
• INTERACTIONS

Subject Categories:

• Organic Chemistry
• Physical Chemistry
• Crystallography
• Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE