December 14-16—SAN DIEGO, CALIFORNIA: Wholesale and retail show; Gem Faire Inc.; Scottish Rite Center, 1895 Camino del Rio S; Fri. 12-6, Sat. 10-6, Sun. 10-5
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Thu Dec 13, 2018 4:32 pm

All times are UTC - 4 hours




Post new topic Reply to topic  [ 8 posts ] 
Author Message
 Post subject: Raman Spectrum of my Missus' engagement ring
PostPosted: Sun May 09, 2010 12:37 am 
Offline
Platinum Member
User avatar

Joined: Tue Jan 02, 2007 8:20 pm
Posts: 2654
I only got one shot at the Raman microscope.This one. We put Leggsie's engagement ring under the 20x objective and fired the various lasers at it.

The diamond is an E color, vvs1, 1.15 carat with moderately strong blue fluorescence.

The Raman spectrum is shown below. Absolutely no emissions except for the characteristic diamond line at 1332 per centimeter. When the applications rep put the cursor on the spike and said it was 1332 I remembered that that was an important diamond signal. Maybe Dr. Alzheimer hasn't caught me yet. :lol:

Image

Although the Raman spectrum is measured in wavenumbers like the IR it is a very different critter.It is light SHIFTED from the exciting wavelength. A laser beam is shined on whatever the specimen is and it makes the molecules shake rattle and roll and they re emit some of the energy. It is similar to fluorescence but about 100 times weaker so much harder to detect. And if the specimen does fluoresce it makes the Raman signal harder to get. So they offer different wavelength lasers in hopes of not stimulating fluorescence. The usual lasers are 785 nanometers, (a solid state InfraRed laser) 633 nanometers (Helium Neon line but now sometimes done with fancy solid state lasers anyway.) or 532 nanometers (Diode pumped solid state green) Sometimes they offer a YAG laser at 1064 nanometers and other lasers are used as well.

The Raman shift always looks the same regardless of the excitation wavelength. It is shifted by characteristic numbers of waves.

Notice that the Y axis is labeled in counts. That is how many Raman photons are emitted. By contrast, the FTIR is an absorbance value just like in UV-VIS.

Monday the guys from Renishaw are bringingtheir Raman unit. Some of the PIs are going to be out of town so I will get to play more. (I think :lol:)


Last edited by G4Lab on Mon May 10, 2010 9:32 am, edited 1 time in total.

Top
 Profile  
Reply with quote  
 Post subject: Re: Raman Spectrum of my Missus' engagement ring
PostPosted: Mon May 10, 2010 5:58 am 
Offline
Site Admin
User avatar

Joined: Fri May 12, 2006 11:24 am
Posts: 7492
Location: Rome, Italy
G4Lab wrote:
Monday the guys from Renishaw are bringingtheir Raman unit. Some of the PIs are going to be out of town so I will get to play more. (I think :lol:)


i can imagine.. :lol:
ciao
albé

_________________
GemmoRaman-532 - GemmoFTIR - GemmoSphere - EXA


Top
 Profile  
Reply with quote  
 Post subject: Re: Raman Spectrum of my Missus' engagement ring
PostPosted: Tue Jun 05, 2012 4:20 pm 
Offline
Established Member

Joined: Sat Jun 02, 2012 12:50 am
Posts: 11
Location: Colombo, Sri Lanka
"The Raman spectrum is shown below. Absolutely no emissions except for the characteristic diamond line at 1332 per centimeter."
It's reciprocal centimeter, or cm-1, if I may say, wich makes a big difference.
Take it easy!
Eric


Top
 Profile  
Reply with quote  
 Post subject: Re: Raman Spectrum of my Missus' engagement ring
PostPosted: Wed Jun 06, 2012 2:58 am 
Offline
Moderator
User avatar

Joined: Thu Dec 13, 2007 3:42 pm
Posts: 4083
Location: the Netherlands
:D


Top
 Profile  
Reply with quote  
 Post subject: Re: Raman Spectrum of my Missus' engagement ring
PostPosted: Mon Jun 11, 2012 4:10 pm 
Offline
Platinum Member
User avatar

Joined: Tue Jan 02, 2007 8:20 pm
Posts: 2654
Quote:
"The Raman spectrum is shown below. Absolutely no emissions except for the characteristic diamond line at 1332 per centimeter."
It's reciprocal centimeter, or cm-1, if I may say, wich makes a big difference.
Take it easy!
Eric


I think you might need to go back, and review your junior high school arithmetic. "Wavenumbers per centimeter" is exactly the same as reciprocal centimeters. Which, if I may say, makes no difference, whatsoever.

Dr. Brian! Dr.Bill!

BTW, we bought the one at the beginning of this thread. Bruker Senterra.


Top
 Profile  
Reply with quote  
 Post subject: Re: Raman Spectrum of my Missus' engagement ring
PostPosted: Mon Jun 11, 2012 8:45 pm 
Offline
Active Member

Joined: Wed Aug 02, 2006 1:10 pm
Posts: 53
Location: Louisville, KY
EthicalGems wrote:
"The Raman spectrum is shown below. Absolutely no emissions except for the characteristic diamond line at 1332 per centimeter."
It's reciprocal centimeter, or cm-1, if I may say, wich makes a big difference.
Take it easy!
Eric


Hello: "1332 PER cm" is the SAME as "1332 cm-1"

_________________
Marty Haske
SAS2000 Spectrophotometer Analysis System
Adamas Gem Lab


Top
 Profile  
Reply with quote  
 Post subject: Re: Raman Spectrum of my Missus' engagement ring
PostPosted: Tue Jun 12, 2012 4:08 am 
Offline
Moderator
User avatar

Joined: Thu Dec 13, 2007 3:42 pm
Posts: 4083
Location: the Netherlands
:D

jee massa, that took you a while...


Top
 Profile  
Reply with quote  
 Post subject: Re: Raman Spectrum of my Missus' engagement ring
PostPosted: Tue Jun 12, 2012 10:46 pm 
Offline
Platinum Member
User avatar

Joined: Tue Jan 02, 2007 8:20 pm
Posts: 2654
:D You were just sitting there, grinning , Jungling. Sometimes also the real world interferes with the virtual. :roll:


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock