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In article <phrjz0#@lynx.unm.edu> swami@chtm.eece.unm.edu (Swami srinivasan) writes:
>
>	have a nagging question...
>
>	He mentioned that fullerenes can also be made by MBE growth.
>

  MBE process is news to me. Did you ask him for references?

>	How does a fullerene form? i would have expected a flat
>thin film of C to deposit. What makes the few atoms that first contact
>the substrate to grow upward, with the "prior" knowledge of  C-60
>geometry? How does the structure actually grow and under what special
>conditions (in an MBE)? Can these be grown with MOCVD?
>

 Fullerenes do grow, quite profusely and in concentric helical pattern,
 on negative electrodes in electrode arc process. These fullerenes are
 being called bucky tubes - for their tubular shapes.
 Reference: S. Iijima, Nature, last year.
 
 I am not aware of C60 growing upward. C60 closes. C60, therefore has
 to begin, grow/extend and then end. 

 Fullerenes are convex structures and follow Euler's theorem of geometry.
 They have to have 12 pentagons. Bucky  tubes have all these pentagons at
 the tube ends. The growth of the bucky tubes therefore begins with pentagons.
 Pentagons lead to curvature. This curvature gives the first direction -
 "growth upward." 

 The helical structure of the each bucky tube easily and elegantly permits
 self growth with prior knowledge - much like the DNA in life forms. Use some
 jelly beans/potato pieces with match sticks/tooth pick and play it out. 
 See Iijima's bucky tube figures in Nature and in Science (last 
 year sometime), to get hints.


>	More generally, how do fullerenes form at all? There must be
>	I hope these aren't silly questions. Any info/references will
>be welcome. i am curious about the topic and slowly getting interested,
>anticipating some non-linear optics applications. 
>
>							swami srinivasan

 Formation mechanism: different processes seem to suggest
 different hypothesis. For the graphite vaporisation processes: the 
 hypothesis that is still not disproved is by
 Smalley et al. (See latest issue of Accounts of Chemical Research - special
 issue on buckministerfullerenes). 

 Your anticipation on nonlinear optics applications is already racing towards
 reality. See recent issues of Nature (Mar or Feb). So don't get interested
 slowly. Plunge. There is too much fun in the global bucky olympics.

T.Y.
----
tyadav@athena.mit.edu