Subject: RE: Is "Vibrational Spectroscopy" generally equals to "IR spectro scopy"?

From: "Shobe, Dave" <[email-masked]>
Date: Thu, 17 Jan 2002 08:46:58 -0500

My own opinion only:

In practice "vibrational spectroscopy" is generally synonymous with "IR
spectroscopy."  However, there is a reason for having the 2 terms, since
they are not *precisely* synonymous, and different concepts are involved in
the 2 terms even if in practice the spectra being discussed are the same.

"Vibrational" spectroscopy refers to the method in which the substance gains
energy as a result of absorption: the energy goes largely into nuclear
motions which involve changing of bond lengths & angles.  "IR" (=
"infrared") spectroscopy refers to the frequencies of electromagnetic energy
being absorbed.  

As for "absorption" spectroscopy (I expect "adsorption" is a mistake, since
I still get those words mixed up on occasion myself :-), this is an entirely
separate issue.  Absorption spectroscopy means that material is gaining
energy at the expense of the electromagnetic field; emission spectroscopy
means that the material is emitting energy as electromagnetic radiation.  

--David Shobe
S黡-Chemie Inc.
phone (502) 634-7409
fax     (502) 634-7724
email  [email-masked]

Don't bother flaming me: I'm behind a firewall.

-----Original Message-----
From: Zhenhua Li [mailto:[email-masked]]
Sent: Wednesday, January 16, 2002 11:37 PM
To: [email-masked]
Subject: CCL:Is "Vibrational Spectroscopy" generally equals to "IR
spectroscopy"?

Hi, Dear listers,
Today several staffs have a discussion about what is the implied or
generally accepted meaning of "vibrational spectroscopy". One guy insisted
that it is generally accepted that when we talked about vibrational
spectroscopy, without specify IR or Raman before it, we must say that it is
an "adsorption spectroscopy".  But I insisted that any spectroscopy that
originated from vibrational adsorption or emission can be called
"vibrational spectroscopy". Thus, when we talked about "vibrational
spectroscopy", we do not really means it is an IR spectroscopy.
This is important since the meaning of this term has appeared in an exam
paper. It is important to ensure not to give students wrong concept.
Thanks a lot.

Li Zhenhua

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