At 01:28 PM 4/20/2007, you wrote:
>>Date: Thu, 19 Apr 2007 12:54:38 -0500
>>From: Shawn Carter <scarter_at_ou.edu>
>>To: susan Alguindigue <SusanA_at_chemdept.chem.ou.edu>
>>
>>We are performing a series of kinetics experiments with the NMR
>>that involve increasing exponential signals. According to page 138
>>of the VnmrJ Liquids NMR User Guide we can use the software to
>>evaluate the data for us. According to the guide, the software
>>uses the following equation:
>>
>>I=A1*EXP(-T/TAU)+A3
>>
>>Are questions are:
>>
>>What are A1 and A3?
>>
>>How does the software find TAU?
How, indeed, does one find tau? 'Tis a consummation devoutly to be
wished. To die, to sleep-- to sleep--perchance to dream of tau: ay,
there's the rub, whence cometh tau? This must give us pause. There's
the respect that this was but one of the despised pangs of learning
in undergraduate chemistry.
Is tau for me the same as tau for others? And what of A1 and A3?
Perish the thought that they be consigned to the realm of
arbitrariness by mere mortals such as us. Much worse the prospect
that tau may be "found" by such a mere thing as "software," for what
is that thing but ware that is soft, with this regard their currents
turn awry and lose the name of action.
We must all seek tau. It resides in our hearts and souls, not just in
some simple table of numbers, such as we may determine by our mortal
choices as being a measurement of man's worth or some interval
between a pulse inverse to most and one of rectitude to the same stage.
And what of A1 and A3? We know not even their dimensions. Thus
conscience does make cowards of us all, but it matters not - for it
is neither A1 nor A3 that we seek, but rather the revelation to us of tau - -
- - which is different for all of us who will shuffle off this mortal
coil. Different especially if we fail to degas our samples to constant T1.
William S.
William C. Stevens, Ph.D. Director
Nuclear Magnetic Resonance Facility
Southern Illinois University
Carbondale, IL 62901
618-453-6498 voice / -6408 fax / 521-9892 cell
http://opie.nmr.siu.edu
Received on Mon Apr 23 2007 - 11:22:15 MST