IRDG 2

INFRA-RED DISCUSSION GROUP
Minutes of 2nd Meeting held in King's College, London, May 26th, 1950

The second meeting of the Infra Red Discussion Group held in London on May 26th was attended by 53 members under the chairmanship of Dr. Martin. The minutes of the first meeting were adopted without comment.

The position with regard to the supply of charts for the recording and duplication of spectra was considered. These could be ordered from Grubb Parsons for immediate delivery at 6d each in lots of 50.

A list was compiled of laboratories having complete copies of the A.P.I. spectra in their possession in order that any member wishing to refer to this volume and having no copy in his laboratory may do so. The compiled list is appended at the end of the minutes.

Dr. Koch, reporting on the results of the comparative measurements of extinction coefficient said that ten different spectroscopists, employing altogether eight different types of spectrometer but one and the same standard cell, had carried out thirteen separate sets of optical density determinations on three standard carbon tetrachloride solutions of pure (99.7%) 1-octene at the 910 cm^-1 band. The concentrations, unknown at the time of measurement, were 0.217, 0.319 and 0.423M. 

The thickness of the standard cell was determined by several investigators by an interference method. 
It appeared that the accuracy of the method is less than generally believed and also depends largely on the
spectrometer employed. Cell thickness values from 0.093 to 0.097m were quoted, although definite evidence was obtained that the cell did not change during the course of the investigation.

In a general discussion on absorption cells Dr. Powell outlined the characteristics of a variable thickness absorption cell he had designed and built. As the patent on this was still pending it was unfortunate that [end of document].