Absorptions between 3000 and 5500 cm(-1) of cyclic O4+ and O4- trapped in solid neon.

Recently, gas-phase absorptions in the 3000-4300 cm(-1) spectral region have been assigned to combination bands built on (ν1 + ν5) of ground-state cyc-O4(+). Other gas-phase experiments identified an electronic transition of cyc-O4(-) complexed with an argon atom between 4000 and 5300 cm(-1). Absorptions that correspond closely to these two groups of bands have been observed in neon-matrix experiments in which both cyc-O4(+) and cyc-O4(-) are trapped at 4.

Infrared spectra of products of the reaction of H atoms with O2 trapped in solid neon: HO2, HO2(+), HOHOH(-), and H2O(HO).

When a Ne/O2 mixture is codeposited at 4.3 K with a Ne/H2 mixture that has been passed through a microwave discharge, the infrared spectrum of the resulting deposit includes prominent absorptions of the three vibrational fundamentals of HO2 and seven relatively weak absorptions in the infrared and near-infrared, only one of them previously reported, that can be assigned to overtones and combination bands of that product. Similar assignments are made for DO2.

The infrared spectrum of HOOH+ trapped in solid neon.

When a Ne:H(2)O(2) mixture is codeposited at 4.3 K with a beam of neon atoms that have been excited in a microwave discharge, three new, photosensitive absorptions appear which can be assigned to the three infrared-active vibrational fundamentals of trans-HOOH(+). When the Ne:H(2)O(2) deposition system is pretreated with the vapors of D(2)O, the product absorptions include new peaks which can be attributed to vibrational fundamentals of trans-HOOD(+) and trans-DOOD(+).

The infrared spectrum of NN···CO+ trapped in solid neon.

Codeposition of a Ne:N(2):CO = 200:1:1 mixture at 4.3 K with a beam of very pure neon atoms excited to their energy levels between 16.6 and 16.

The infrared spectra of BF3+ and BF2OH+ trapped in solid neon.

Observations on a Ne:BF(3) = 400:1 mixture into which a trace of normal or isotopically enriched water had been introduced, codeposited at 4.3 K with a beam of neon atoms that had been excited in a microwave discharge, demonstrate that a pair of absorptions at 1662 cm(-1) and 1722 cm(-1) that were previously assigned to the two boron-isotopic species of BF(3)(+) should be reassigned to a BF(2) stretching fundamental of BF(2)OH(+). The OH stretching fundamental of that product was identified for the first time at 3240 cm(-1).

The infrared spectra of C2H4(+) and C2H3 trapped in solid neon.

When a mixture of ethylene in a large excess of neon is codeposited at 4.3 K with a beam of neon atoms that have been excited in a microwave discharge, two groups of product absorptions appear in the infrared spectrum of the deposit. Similar studies using C(2)H(4)-1-(13)C and C(2)D(4) aid in product identification.

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This article tells of a lifelong fascination with light, a messenger bearing information from realms ranging from the galactic to the submicroscopic. Personal interactions have shaped and informed this life journey. Accounts of some of the most important of these are related.

A 2E''-X2A2' transition of NO3 trapped in solid neon.

NO(3) has been stabilized in a neon matrix at 4.3 K in sufficient yield for detection of the absorptions between 7000 and 10,000 cm(-1), which arise from vibronically allowed transitions from the ground state to levels of the A (2)E'' state. The results confirm and somewhat extend previous gas-phase observations for (14)N(16)O(3).

Conflicting observations resolved by a far IR and UV/Vis study of the NO3 radical.

By codeposition of NO/Ne and O(2)/Ne mixtures at 6 K, weakly bound complexes between O(2) and NO are formed. They exhibit a strong, structured charge transfer UV band at lambda(max)=275 nm. The UV band disappears during UV irradiation of the neon matrix, while the visible spectrum of the NO(3) radical appears.

The infrared spectroscopy and photochemistry of NO(3) trapped in solid neon.

NO(3) can be stabilized in solid neon either by codeposition at 4.3 K of a Ne:O(2) mixture with a Ne:NO mixture that has been passed through a microwave discharge or, in higher yield, by codeposition of a Ne:NO mixture with a Ne:O(2) mixture, followed by annealing of the deposit at approximately 7 K and exposure of the solid to near ultraviolet radiation. All of the previously reported bands of NO(3) between 700 and 3000 cm(-1) were observed, most with neon-matrix shifts of less than 2.

Infrared spectra of ClCN+, ClNC+, and BrCN+ trapped in solid neon.

When a mixture of ClCN or BrCN with a large excess of neon is codeposited at 4.3 K with a beam of neon atoms that have been excited in a microwave discharge, the infrared spectrum of the resulting solid includes prominent absorptions of the uncharged isocyanide, ClNC or BrNC, and of the corresponding cation, ClCN+ or BrCN+. The NC-stretching fundamentals of the isocyanides trapped in solid neon lie close to the positions for their previously reported argon-matrix counterparts.

Infrared spectroscopy and photochemistry of NCCN+ and CNCN+ trapped in solid neon.

When a Ne:NCCN sample is codeposited at 4.3 K with neon atoms that have been excited in a microwave discharge, the infrared and near infrared spectra of the resulting deposit include a prominent peak at 1799.5 cm-1, previously assigned to nu3 of NCCN+, and several new absorptions at higher frequencies which are contributed by combination bands of ground-state NCCN+.

Infrared absorptions of NH3(H2) complexes trapped in solid neon.

When a very small concentration of H2 is added to a Ne:NH3=800:1 sample and the resulting mixture is deposited at 4.3 K, a new absorption appears at 4151.1 cm(-1) which can be assigned to the H2 stretching fundamental of H2 (j=1) complexed with NH3.

Infrared spectra of NH2NO, NH2NO+, and NNOH+ and of the N2...H2O complex trapped in solid neon.

When a Ne:H2:N2O mixture is co-deposited at 4.3 K with a beam of neon atoms that have been excited in a microwave discharge, NH2NO+ is stabilized in sufficient concentration for detection of five of its vibrational fundamentals. Their assignments are supported by isotopic substitution studies and by the results of unrestricted B3LYP/cc-pVTZ calculations.

Infrared spectrum of the NH4-d(n)+ cation trapped in solid neon.

The NH4+ cation has been stabilized in solid neon in sufficient concentration for the identification of both of its infrared-active vibrational fundamentals, which appear within a few wavenumbers of the gas-phase band centers. Systematic alteration of the concentrations and positions of introduction of NH3 and H2 in the discharge sampling experiments demonstrated that the highest yield of NH4+ resulted when both the NH3 and the H2 were introduced downstream from a discharge through pure neon. In this configuration, each of these molecules can be ionized by excited neon atoms and their resonance radiation (16.

Vibrational and electronic spectra of neutral and ionic combustion reaction intermediates trapped in rare-gas matrixes.

The infrared absorptions of neutral and ionic molecules trapped in solid rare-gas matrixes lie close to the gas-phase band centers, and perturbations in valence electronic transitions are relatively small. Since molecular diffusion through rare-gas solids is inhibited, matrix isolation studies provide a valuable tool for obtaining the infrared and visible-ultraviolet spectra of combustion reaction intermediates. The results of studies of the spectra of HCO, trans-HOCO, HCC, C2-, CO2+, CO2-, C2H2+, C3H4+, HCOOH+, HOCO+, and HCO2- summarized in this Account illustrate the importance of supplementing familiar generalizations with experimental observations.

Infrared absorptions of the H(2)O ... H(2) complex trapped in solid neon.

When a sample of neon to which have been added less than 1% each of H(2) and H(2)O is deposited at 4.3 K, the infrared spectrum of the resulting solid includes an absorption by the vibrational fundamental of H(2), which is normally infrared inactive. New absorptions are also associated with the vibrational fundamentals of the H(2)O in the sample.

The spectroscopy of molecular reaction intermediates trapped in the solid rare gases.

The trapping of neutral and electrically charged molecular reaction intermediates in the solid rare gases and the characterization of these intermediates by vibrational and electronic spectroscopy are surveyed. Spectral data for reaction intermediates trapped in solid neon and argon are compared with the corresponding data obtained from gas phase studies and from quantum chemical calculations. Emphasis is placed on recent progress, including the production, stabilization, and spectroscopic study of highly reactive small molecular ions and the use of ab initio and density functional calculations for the identification of reaction intermediates.