Infrared & Raman Discussion Group Meeting

2. Infrared & Raman Discussion Group Meeting

Kings College London
December 13th 2001

Editor

The IRDG holds 4 meetings each year, the Christmas one always being at King’s College in the Strand, London. The IRDG is a very well established organisation with about 185 members. It has held roughly this number of meetings over very many years. The Christmas meetings is always built around an excellent Christmas lunch, the booze being funded by one of the major instrument Companies. This year was Perkin Elmer’s turn.

Dr. J.A Reffner of SensIR in Danbury, Conn. Started the proceeding by giving us an overview of the vibrational spectroscopy business. He pointed out that the US sales were around $1.3 x 108 and had been at this level for 1997-2000. On the other hand the US economy had done well in this period. The industry was mature. Its days of rapid expansion were over. Further, the US sales are split amongst 17 companies so no one is really large. At the end of Dr Reffner’s talk I pointed out that one of the reasons for the stagnation in the industry was that in Universities IR, Raman and NIR were simply not taught. The emphasis was on NMR and MS.He agreed that this is a problem.

Reffner then went on to describe a series of applications of IR in forensic work, usually involving IR microscopy. All were fascinating and some just plain gory! e.g. it seems that some lad in the US murdered his wife, froze the body and then sliced it up into logs with a chain saw. He then hired a wood chipping machine and yes, you’ve guessed it, chipped up the logs. It seems someone thought it was rather odd to be doing this in mid winter and the police took an unfriendly interest. Amazingly in all the mess a tiny piece of finger-nail was found and checked by IR microscopy. The nail varnish (polish) matched that found in the familial bathroom! Other examples involving investigations at the first World Trade Centre bombing and bullets then followed. Dr Reffner completed his talk with a description of his company’s IlluminateIR – a tiny instrument built onto a microscope and showed examples of its applications.

The theme of the meeting, ‘new techniques and developments from the instrument manufacturers’ was then developed by Dr Neil Lewis of Spectral Dimensions of Olney Maryland. Neils’ subject was array detectors and their use in infrared microscopy. He showed superb images of brain tissue taken with a mercury cadmium telluride array 1024 x 1024 pixels in size. He pointed out that as products become more complex and/or people are moving into the biological field, the need for imaging at ever increasing resolution was growing. As an example, he showed a polymeric layer system where rogue inclusions could be analysed.

Using an NIR tuneable filter detector on a microscope, images can be examined to distinguish pseudo identical tablets, to explore mixing at interfaces or to study blending e.g. mixing excipient and active constituents in pharmaceutical products.

Dr Lewis then went on to show how contamination can be discovered in animal protein – a highly topical field of course in the UK. If the feed is thinly spread on a surface and the picture obtained in specific infrared wavelengths a particle of contaminant can be identified regardless of its overall bulk concentration.

To conclude, cost raised its ever present head. NIR arrays are reasonable in cost ~$0.30/pixel, but in the MIR there is a real problem. 64 x 64 pixels can cost as much as $35,000.

Contributions from the US continued with an account of new measurements in inelastic neutron scattering from Prof Bruce Hudson of the University of Syracuse. His interest in INS includes a variety of problems e.g. dodecahedron C20H20 an isohedral and hence a highly symmetric molecule. Almost no modes appear in the IR and Raman – 11 in a total of 30 i.e. 19 are ‘silent. The INS spectrum has no selection rules and all are seen. It also seems that the frequencies and the intensity of the INS bands are ‘easy’ to predict. The point was demonstrated.

Hydrogen is an excellent (in fact overwhelming) neutron scatterer so the method is ideal for studying hydrogen bonding. The example of oxamide was shown.

Bruce Hudson also discussed the study of overtones in both neutron and resonance Raman scattering.

After the lunch, the unfortunate lecturers have to talk through an alcoholic fug and shout over the snores. Well our speakers were so interesting insomnia seemed to set in with a vengeance.

Robert Hoult of Perkin Elmer kicked off with a description of the company’s new imaging mid infrared microscopic instrument entitled Spotlight. I wont give an account here as the technology is subtle and if not explained carefully is hard to understand. Dr Hoult and his colleague Dr Richard Spragg have sent me material to write a feature on this new machine and it will appear in the next edition.

Prof.Howell Edwards then spoke last (not a particularly popular spot on the agendum). Howell gave a talk at the British Museum but this one was totally different. Howell Edwards works with the British Antartic Survey. On Antartica, there are areas incredible inhospitable to growth. There are dessert areas with almost zero humidity, at temperatures around -35ºC suffering high winds and exposed to intense UV radiation i.e. the sort of conditions as hostile as those that exist on Mars. Now, there is a plan to develop an ultra lightweight Raman instrument, which will be landed on Mars. A probe will sample the surface of the planet and the infrared instrument will search for evidence of biological activity. Howell will be involved in this programme. The test bed area is to be the cold desserts of Antartica. Howell brought us up-to-date with this incredibly demanding and fascinating project.

The rocks in Antartica are eroded by wind borne abrasives yet organic species can be found beneath the surface. Growth rates are unbelievably slow – carbon turnover takes 10,000 years! However, lichens can survive and in fact develop roots penetrating centimetres into the rocks. These materials give excellent Raman spectra. Further the technique can be used to identify the minerals involved [see report on British Museum meeting]. Howell Edwards concluded by briefly describing the Raman instrument currently under development for the Mars trip.

To conclude – a really interesting meeting, superb lectures and fascinating material. I can’t understand why more UK and geographically close spectroscopists don’t join the IRDG – the subscription is almost zero and the meetings are an ideal way of meeting and discussing problems with colleagues – oh and don’t forget the Christmas lunch each year! More details of the IRDG are given below and there’s a link to an application form.

The U.K. Infrared and Raman Discussion Group, IRDG

The Infrared and Raman Discussion Group, the IRDG, was formed in 1950. It is one of the oldest independent spectroscopy and specialist subject groups in the U.K., and as such is able to put on high quality, low registration fee meetings. Although a national organisation, the IRDG has several overseas members. It caters for all who are interested in the theory, practice and teaching of vibrational spectroscopy, in particular infrared and Raman spectroscopy. Membership is drawn from a wide cross-section of experience, expertise and interest areas. Members come from industry, government and academic institutions and spectrometer manufacturers and specialist accessory suppliers.

The IRDG normally holds a minimum of three one-day technical presentation and discussion meetings a year. These are held at varied locations around the U.K., excepting its very popular ‘traditional Xmas lunch’ meeting, which is held in London at King’s College around 13-20 December each year. Meetings feature talks by both members and non-members of the IRDG. Invited speakers from overseas are a regular feature, particularly at the December meeting, when circumstances make it economic for them to be invited. Since 1994, the IRDG has organised and sponsored approximately annually a one-day student prize award meeting; the Martin & Willis monetary prize, awarded in memory of two past long-serving chairman of the IRDG, is awarded for an oral presentation. Additional prizes are also awarded for oral and poster presentations. Student participants in this meeting do not have to be an IRDG member. Another regular feature in the IRDG calendar is a course on the ‘Interpretation of Infrared and Raman Spectra’, held at a U.K. university site.

Many activities of the Group, such as its ‘Xmas meeting’, its Martin & Willis student prize meeting, and its courses, receive regular generous support, both in monetary sponsorship and personnel time and equipment from spectrometer manufacturers and specialist accessory suppliers.

The 3-year membership fee is presently £15, with a special rate of £3 for bone fide students, unemployed and retired members. Full details of its committee, future and many past meetings, and much more may be found on the IRDG web site at http://www.irdg.org/ .

Click here to go to an Application Form, which you can print off, complete and return as applicable.

REF: P.J.Hendra. Int.J.Vibr.Spec., [www.irsg.org/ijvs] 5, 6, 2  (2001)