Frozen inert gas matrices of N2 and Ar containing 02 and In or Ga atoms have been prepared by matrix isolation techniques and studied by infrared absorption spectroscopy. Analyses of the spectra have shown that these reagents react to produce metal superoxide molecules, M+02", which are similar to those of the alkali and alkaline earth metals. The stretching modes of these species absorb in the regions of 1080-1090 cm"1 for r1(A1), 330-380 cm"1 for * 2( ), and 270-290 cm"1 for ^(Bj). In addition to the superoxides, various aggregate species are produced. One of these has been identified as the superoxide dimer, which apparently has an 02M-M02 structure of I)2d symmetry. Another aggregate has been identified as a rhombic M02M species which is formed by the addition of a metal atom to the superoxide. Small quantities of the suboxide dimer (ln20)2 also were detected in these matrices. The evidence indicates that this species was formed by the addition of an In atom to each oxygen of the In02In(D2ft) species. This dimer is of interest because it is readily formed by aggregation of the suboxide monomer in experiments involving the vaporization of the condensed oxide systems.

N a t i o n a l A e r o n a u t i c s and Space A d m i n i s t r a t i o nLewis Research Center C l e v e l a n d , O h i o 44135 SUMMARYThe r e a c t i o n s o f l i n e a r p e r f l u o r o p o l y a l k y l e t h e r (PFAE) l u b r i c a n t s w i t h a-FezO3 and Fe203-based s o l i d s u p e r a c i d s were s t u d i e d . a-Fe2O3 proceeds i n two s t a g e s . The first s t a g e i s an i n i t i a l slow c a t a l y t i c d e c o m p o s i t i o n o f t h e f l u i d . T h i s r e a c t i o n r e l e a s e s r e a c t i v e gaseous p r o d u c t s which a t t a c k t h e m e t a l o x i d e and c o n v e r t i t t o FeF3. more r a p i d d e c o m p o s i t i o n o f t h e f l u i d , e f f e c t e d b y t h e s u r f a c e FeF3. A s t u d y of t h e i n i t i a l breakdown s t e p was p e r f o r m e d u s i n g a-Fe203, a-FezO3 p r e c o n v e r t e dt h e breakdown r e a c t i o n i n v o l v e s a c i d i c a t t a c k a t f l u o r i n e atoms on a c e t a l carbons i n t h e l i n e a r PFAE. P o s s i b l e approaches t o combat t h e p r o b l e m a r e o u t 1 i ned .The r e a c t i o n w i t hThe second s t a g e i s a

High-level ab initio calculations have been performed on the exo and endo isomers of gas-phase tetrahydrodicyclopentadiene (THDCPD), a principal component of the jet fuel JP10, using the Gaussian G(x) and G(x)(MP(x)) composite methods, as well as the CBS-QB3 method, and using a variety of isodesmic and homodesmotic reaction schemes. The impetus for this work is to help resolve large discrepancies existing between literature measurements of the formation enthalpy Delta(f)H degrees (298) for exo-THDCPD. We find that use of the isodesmic bond separation reaction C(10)H(16) + 14CH(4) --> 12C(2)H(6) yields results for the exo isomer (JP10) in between the two experimentally accepted values, for the composite methods G3(MP2), G3(MP2)//B3LYP, and CBS-QB3. Application of this same isodesmic bond separation scheme to gas-phase adamantane yields a value for Delta(f)H degrees (298) within 5 kJ/mol of experiment. Isodesmic bond separation calculations for the endo isomer give a heat of formation in excellent agreement with the experimental measurement. Combining our calculated values for the gas-phase heat of formation with recent measurements of the heat of vaporization yields recommended values for Delta(f)H degrees (298)liq of -126.4 and -114.7 kJ/mol for the exo and endo isomers, respectively.

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