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VERSION:2.0
PRODID:-//RLASKEY//CALENDEROUS//EN
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METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20260814T215803Z
LAST-MODIFIED:20130226T163009Z
DTSTART:20130225T210000Z
DTEND:20130225T220000Z
UID:event1064@bu.edu
URL:http://physics.bu.edu/internal/events/show/1064
SUMMARY:Soft X-ray Studies of Cycloparaphenylene
DESCRIPTION:Featuring Dave Newby\n\nPart of the Preliminary Oral Exam.\n\nE
	xamining Committee:  Kevin Smith\, Karl Ludwig\, David Campbell\, Rob Carey
	\, Soumendra Basu\n\nAbstract:\n\nCarbon allotropes continue to be a fascin
	ating and fertile ground for materials research. Cycloparaphenylenes (CPPs)
	 are the shortest possible segment of armchair nanotubes\, and are composed
	 of an integer number [n] of benzene rings arranged in a ``hoop''. Recent i
	nterest in this molecule stems from its possible use as a building block fo
	r nanotubes. Non-[n]-selective synthesis of CPPs was first achieved in 2008
	 [1]\, and subsequent techniques continue to develop for selectively creati
	ng various [n] values in small quantities. Early UV-Vis studies of CPP in s
	olution revealed a blue-shifted emission that increased with larger ring si
	ze[2]. This defies the typical trend for cyclic organic molecules\, in whic
	h we expect the exact opposite trend. This quality alone has prompted many 
	theoretical attempts to fully explain the optoelectronic behavior of the [n
	]-CPPs[3]. In 2012 the Jasti group at BU pioneered a technique for producin
	g crystalline [8]- and [10]-CPP at the gram-scale[4]. These previously unat
	tainable quantities are sufficient for molecular beam epitaxy (MBE) deposit
	ion on substrates\, which lends itself perfectly to soft x-ray electronic s
	tructure analysis. Synchrotron radiation provides enough flux and monochrom
	atic selectivity to study a number of unique electronic properties\, and th
	e X1B endstation at the NSLS hosts a number of experimental tools for exact
	ly such analysis. We present a complement of results from various technique
	s\, including x-ray absorption\, emission\, and photoelectron spectroscopie
	s. The MBE deposition of CPP thin films will also be discussed\, along with
	 information on the orientation of CPP molecules on the substrate. The char
	acterization provided by these techniques facilitates comparison with DFT\,
	 and we will elucidate our findings with DFT calculations. These measuremen
	ts provide an unprecedented view of this new and exciting molecule\, and ma
	y provide a stepping-stone to further refinement of a DFT-based understandi
	ng of its orbital structure.
LOCATION:PRB 365\, 3 Cummington Mall\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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