ENGINEERING RESEARCH INSTITUTE UNIVERSITY OF MICHIGAN ANN ARBOR EIGHTH QUARTERLY REPORT ON INFRARED STUDIES OF CRYSTALS (PERIOD: 16 May 1953 to 15 August 1953) BY G. B. B. M. SUTHERLAND Principal Investigator R. T. MARA C. Y. PAN LIANG Project M957 SIGNAL CORPS, DEPARTMENT OF THE ARMY CONTRACT DA 36-039 sc-5581 SC PROJECT 152B-0, DA PROJECT 3-99-15-022 SQUIER SIGNAL LABORATORY, FORT MONMOUTH, N.J. September, 1953

TABLE OF CONTENTS Page I. INTRODUCTION 1 II. ACCOUNT OF WORK DONE 2 III. FUTURE PROGRAM 3 ii

INFRARED STUDIES OF CRYSTALS EIGHTH QUARTERLY REPORT COVERING THE PERIOD 16 MAY 1953 to 15 AUGUST 1953 I. INTRODUCTION Purpose of the Research This has been outlined previously and need not be repeated. The objectives are essentially as stated in the Second Annual Report (June 1953). Personnel The following have been engaged on the work reported here: Prof. G.B.B.M. Sutherland, Director (Part time) Mr. R. T. Mara (Half time) Mrs. C. Y. Pan Liang (Half time) Mr. A. Dockrill (Part time as laboratory technician)

II, ACCOUNT OF WORK DONE (A) Diamond The work described in Technical Report No. 1 is being prepared for publication. (B) Brucite A full account of the work done by R. T. Mara on brucite up to August 15, 1953 has been prepared and will be submitted shortly as Technical Report No. 2. A brief account of this work has been submitted to the Journal of the Optical Society and accepted for publication in the near future. (C) Mica The dichroism of the OH stretching frequencies in biotite has been studied systematically and a possible theory proposed to explain the observed results. Further experiments are now in progress to test the theory. 2

III. FUTURE PROGRAM (A) Diamond The whole problem of the two types of diamond will be reviewed afresh in the light of the new data obtained here and also by Grenville Wells in England, (B) Brucite The theoretical interpretation of Mara's results will be tackled in detail. Similar experimental studies are planned for similar hydroxides* (C) Mica An attempt will be made to determine the orientation of the OH ions in biotite. A search will be made for oxonium ions in mica. (D) Concentrated Arc Source It is hoped that the defects in this source (cf. Second Annual Report) can be removed. 3