Upon vacuum-ultraviolet photolysis of H2O in a CO matrix at 14°K, infrared absorptions of HCO, H2CO, HCOOH, and CO2 become prominent. Furthermore, new absorptions due to reactive product species appear at 615, 620, 1077, 1088, 1160, 1261, 1797, 1833, 3316, and 3456 cm−1. These absorptions diminish in intensity when the sample is subjected to radiation in the 2000–3000-Å spectral range. Detailed consideration of the processes which may occur in this system and extensive isotopic substitution studies support the assignment of these absorptions to the cis and trans stereoisomers of H–O–C=O, produced by the reaction of OH with the CO matrix. Valence force potentials having only small contributions from interaction terms have been found which correspond to a physically reasonable vibrational assignment and which satisfactorily reproduce the pattern of observed frequencies for the various isotopic species of both cis- and trans-HOCO. Evidence suggests that cis- and trans-HOCO photodecompose to produce H atoms and CO2.
The infrared spectra which result when samples of NO2 are codeposited with the various alkali metals in an argon matrix at 4 or at 14°K are consistent with the occurrence of strong charge-transfer interaction. In addition to isolated NO2−, previously identified in this system, ion pairs of general formula Mx+NO2− are stabilized. When NO is substituted for NO2, the infrared spectrum of the initial deposit shows an absorption between 1350 and 1375 cm−1 which can be assigned to the NO− stretching fundamental of Mx+NO− ion pairs, in good agreement with the vibrational spacing recently reported for ground-state NO− in the gas phase. Weak charge-transfer interaction occurs between alkali-metal atoms and N2O in an argon matrix environment. Results of the present experiments can be explained by postulating that the upper, predominantly ionic state of the charge-transfer complex decomposes producing O−, which may diffuse through the matrix. A new absorption which appears at 1205 cm−1 has tentatively been assigned to ν4(b1) of a planar O2N=N− anion. In studies of the interaction of sodium atoms with Ar:NO:N2O mixtures, mercury-arc irradiation of the sample leads to the appearance not only of the N2O2− absorption, but also of absorptions due to isolated NO2− and to Nax+NO2−.
Yes, since V does not have sites both in X and Z, it must be a subfigure of XV, YZ, or both. To be specific, suppose V is a subfigure of XV. By hypothesis PIV} is consistent with PIXY}, and we have shown that PIXY} is consistent with P{U}. Therefore, since V is a subfigure of XV, which in turn is a subfigure of U, it follows that P{ V} is consistent with P{U}=P{XY}P{YZ}/P{ V}. Statement (b) is proven by noting P{ U} = P{XYZ} = P{ Y} Py{XZ} and P{ U} = P{ X Y} P{ YZ} / P{ Y} = P { Y} Py{ X} Py{Z} ;thus Py{XZ} = Py{X} Py{Z}. Equations (6) and (7) now lead to the desired result. THE JOURNAL OF CHEMICAL PHYSICS To prove (c), we first write S(P{ UI) = S(P{XYZI) = S(P{ Y}) + LP{ Yl S(Py{XZ}), y in accordance with Eq. (2). A well-known theorem of information theory!2 states S(Py{XZ}) S S(Py{X}) + S(Py{Z}). Therefore S(P{ U})::; S(P{ Y}) + LP{ Y} S(Py{X}) y + LP{ YI S(Py{Z}) , y or with the aid of Eq. (2), S(P{ U})::; S(P{XY}) +S(P{ YZ}) -S(P{ Y}).12Vacuum-ultraviolet photolysis of HCN isolated in Ar and N2 matrices at 14°K is found to lead to the production of HNC in concentration sufficient for direct infrared observation of all three vibrational fundamentals. The spectrum of this species is found to be appreciably perturbed by the presence of N2. The force constants and thermodynamic properties of HNC have been revised to the values appropriate to this species in an environment free of perturbation by an adjacent N, molecule. The free radical CN is also produced in these systems in concentration sufficient for direct observation not only of the B (2];+)-X (2];+) transition but also of the ground-state vibrational fundamental. Isotopic data supporting this identification are presented. Upon vacuum-ultraviolet photolysis of matrix-isolated FCN, two infrared absorptions appear which can be identified with the stretching fundamentals of the species FNC. In analogous experiments on the species CICN and BrCN, infrared absorptions tentatively assigned to CINC and BrNC have been observed.
The photoproduction of H or D atoms from a variety of sources in a carbon monoxide matrix or in an argon matrix to which a small concentration of carbon monoxide has been added leads to the appearance of prominent ultraviolet absorptions between 2100 and 2600 Å, all of which may be assigned to HCO or DCO. Both the CO-stretching and the bending vibrational modes are appreciably excited in the transition. Evidence is presented indicating that the transition observed in the matrix experiments is the same one responsible for the hydrocarbon flame bands. Using the frequencies observed in the matrix experiments, a tentative assignment for the hydrocarbon flame bands has been proposed which is in reasonable agreement with the observed band structure of the emission system. In the upper state, the carbon and oxygen atoms of HCO are approximately singly bonded. Observation of the infrared absorption frequencies of isotopically substituted HCO in an argon matrix has prompted reconsideration of the valence force field appropriate to ground-state HCO. Interaction between the CH-stretching and the CO-stretching modes has been found to play an important role. Factors leading to the stabilization of HCO in an argon matrix in the present experiments, in contrast to the results of previous studies, are discussed.
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