Subject: Scanning Probe Microscopy

From: "C.F. Matta" <[email-masked]>
Date: Fri, 5 Feb 1999 09:59:14 -0500 (EST)

Hi everybody,

First:
  I would much appreciate if you could point to me recent publications 
about modeling/computational studies of the interaction of the tip with
the substrate in Atomic Force Microscopy (AFM) or/and Scanning Tunneling
Microscopy (STM).  

Second:
  In STM, a typical separation from the tip to the substarte is 3-10 A,
i.e. the tails of the wavefunctions of the tip and of the substrate are
crucial. Gaussian functions are not behaving physically at long distances.
Moreover, if the substrate consists of different atoms described with
basis functions decaying at different rates, this will overemphasize the
peacks due to the one decaying slower (the true wavefunction decays
at a single rate).  The Linearized Augmented PlaneWave method (LAPW), due 
to Tersoff & Hamann, is supposed to remedy for this.  
	(1) Is there other methods better than LAPWD?
	(2) Can one implement LAPWD in, say GAUSSIAN or GAMESS?
	(3) If the answer to (2) is YES, then HOW?
	(4) If NO, then what program(s) implements this method? 
	(5) Other suggestions?

Thank you all very much.  I will summarize.

Cherif
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 Cherif F. Matta		  	tel. (905) 525-9140 ext. 22502
 Chemistry Department                   fax  (905) 522-2509
 McMaster University                      
 Hamilton, Ontario, CANADA L8S 4M1.
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