Report
SOMEONE YOU SHOULD KNOW
LET O U R CATALOG G6 INTRODUCE Y O U T O THE W O R L D OF PCR.
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Are y o u engaged in Research on FLUORINE c o n t a i n i n g compounds? D o SILICON organics hold your attention? Catalog C6 contains one of the most c o m p l e t e listings of these c o m p o u n d s to be f o u n d anywhere. W e ' r e not l i m i t e d to these fields of chemistry, many other c o m p o u n d s w i l l be f o u n d in this catalog. G6 is more than just a price list, M o l e c u l a r W e i g h t s and Physical Properties are listed for your convenience.
Chemists
References
For your copy cal 1904 376-7522 or w r i t e
PCR, INCORPORATED P.O. Box 1466-Gainesville, Florida 32601 Formerly Peninsular ChemResearch Inc.
Anaiytical
configuration and orientation. It is assumed that if a change of molecu lar configuration occurs this will cause excited-state absorption to be relatively small. The ruby funda mental is hydrogen-Raman-shifted to 10,245 cm - 1 to supply the second pulse. This interrogating pulse fre quency is not absorbed by the ground-state molecules or by mole cules in the excited state which have assumed a nonplanar configuration. However, it possesses sufficient en ergy to pump the molecule from the first excited electronic level to the second if the excited molecule re mains planar. When the exciting and interrogat ing pulses arrive at the same time, the interrogating pulse is absorbed strongly because of the relatively large number of molecules in the first excited state. As one delays its arrival the intensity of the transmitted interrogating beam in creases. The increase in transmis sion can be interpreted as arising from the decay of molecules in the excited state either to the ground state or to a twisted, nonabsorbing configuration. If the latter is the case, this experiment would indi cate that the molecule changes its nuclear configuration in the excited state; that is, the change in trans mitted intensity measures the dy namic configuration changes. Pre liminary experiments show that the repopulation of the ground state takes ~ 1 0 - 1 1 sec while the popula tion of planar molecules in the ex cited state decreases at a rate about five times faster. In further experi ments we hope to probe the mole cule during this proposed configurational distortion from the excited state to the "disturbed transition state."
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(1) G. R.- Fowles, "Introduction to Mod ern Optics," Holt, Rinehart and Win ston, New York, 1968. (2) R. W. Hellwarth in "Advances in Quantum Electronics," J. R. Singer, Ed., Columbia University Press, N e w York, 1961. (3) A. Eckhardt, R. W. Hellwarth, F . J. McClung, S. E . Schwarz, D . Werner, and E . J. Woodbury, Phys. Rev. Lett. 9,455 (1963). (4) P . A. F r a n k e n and J. F . Ward, Rev. Mod. Phys. 35, 23 (1963). (5) W . Kaiser and C. G. B . Garrett, Phys. Rev. Lett. 7, 229 (1961). (6) P . M. Rentzepis and Y. - H . Pao, Appl. Phys. Lett. 5, 156 (1964).
Circle No. 123 on Readers' Service Card 32 A
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(7) Y. - H . Pao and P. M . Rentzepis, Appl. Phys. Lett. 6, 93 (1965). (S) G. Porter, Nature (London) 215, 502 (1967). (9) G. E . Busch, R. T . Mahoney, R. I . Morse, and K. R. Wilson, / . Chem. Phys. 51,449 (1969). (10) J. R. N o v a k and M . W. Windsor, Proc. Roy. Soc, London A308, 95 Q96S). (11) G. Porter and M. R. Topp; Proc. Roy. Soc., London A315, 163 (1970). (12) J. A. Giordmaine, P . M . ;Rentzepis, S. L. Shapiro, and K. Wécht, Appl. Phys. Lett. 7, 216 (1967). ,•' (13) P . M . Rentzepis and M . A. Duguay, Appl. Phys. Lett. 7, 218 (1967). (14) F o r a review, see F . P . Schâfer, Angew. Chem., Int. Ed. Engl. 9, 9 (1970). (15) P . M . Rentzepis, Chem,. Phys. Lett. 2, 117 (1968). (16) P . M. Rentzepis, Chem. Phys. Lett. 3,717 (1969). (17) P . M . Rentzepis, unpublished results. (18) P . M . Rentzepis, unpublished results.
Addendum
W i t h regard to the article " R a d i o active I n e r t Gases—Tool for Analysis of Gases, Liquids, and Solids" [ANAL. C H E M . 42 (9), 17A (1970)], the Editors wish to include reference to U.S. P a t ent N o . 3,451,778, issued to R. E . Fearon, which embraces some of the radioactive labeling concepts included in the article. T h e Editors also wish to point out the existence of several articles and government reports t h a t will enhance the reader's knowledge in this important field of research : (1) I ) . I. Chleok. and C. A. Ziegler, Nucleonics 17, 130 (1959), for preparation of M Kr-labeled clathrates b y crystallization from the melt. (2) D . I. Chleck and G. A. Ziegler, Int. J. Appl. Radiât. Isotop. 7, 141 (1959). (3) O. Cucchiara, P . Goodman, and R. Rex, U.S. A E C Report N Y O 3735-1 ( M a y 1968). (4) O. Cucchiara, P . Goodman, and T. Donahue, Technical Report A F R P L - T K - 6 8 - 2 3 3 , U S A F Rocket Propulsion Lab., Edwards, Calif. (November 1968). (5) P . Goodman and T . Donahue, U.S. A E C Report WYO-4069-1 (March 1970). (6) O. Cucchiara a n d ^ P . Goodman, Mater. Eval. 25, 109 (1967). (7) P . Goodman and M . R. Ronayne, Technical Report AFML-TR-65-66, U S A F Materials Lab., Wright P a t terson AFB, Ohio (March 1965). (8) J. E . Carden, Isotop. Radiât. Technol. 3(3), 206, 228 (1966) ; 3(4), 318, 337 (1966) ; 5(2), 104 (1967-8). (9) J. E . Carden, Oak Ridge National Laboratory Report O R N L - l l C - 1 3 (July 1969). Also, we wish to point out t h a t " K r y p t o n a t c s " is a registered trademark of Panametrics, Inc.
