P. D. Maker

Fourier transform IR spectroscopic observation of pernitric acid formed via HOO + NO2 → HOONO2

Abstract Kinetic and spectroscopic evidence has been found for the formation of pernitric acid via HOO + NO2 → HOONO2 using Cl-atom sensitized oxidation of H2  NO2 mixture and a Fourier transform IR spectroscopic detection method.

Spectroscopic and kinetic studies of a new metastable species in the photooxidation of gaseous formaldehyde

Abstract Fourier transform infrared spectroscopy has been employed to study the mechanism of formaldehyde photooxidation in dilute gaseous mixtures of Cl 2 and CH 2 O (ppm level) and H 2 , O 2 , and N 2 ( P T ≈ 700 Torr), temperature, 25 ± 2°C. Infrared absorption bands due to a new metastable compound were observed in addition to those of the expected products: HCl, HCO 2 H, CO, and H 2 O 2 . The transient species was tentatively identified as hydroperoxy-hydroxy-methane (HO 2 CH 2 OH), which was presumably formed through the reaction, HO 2 + O 2 CH 2 OH → HO 2 CH 2 OH + O 2 .

An FTIR study of mechanisms for the HO radical initiated oxidation of C2H4 in the presence of NO: detection of glycolaldehyde

Using the long-path FTIR method, glycolaldehyde, CH2(OH)CHO, was detected among the products in photolysis of mixtures containing C2H4, NO and RONO (R = alkyl group) at ppm concentrations in air. The results suggest the occurrence of both unimolecular dissociation and O2 reaction of an oxy-radical, CH2(OH)CH2O, formed in the HO-initiated oxidation of C2H4 in the presence of NO.

Hyper-raman spectra of methane, ethane and ethylene in gas phase

Abstract We report here observations of laser-induced non-linear light scattering, both elastic and inelastic (hyper-Raman), from methane, ethane and ethylene. Observations on several other molecules, mainly substituted methanes and ethanes, will be reported elsewhere.

Analysis of Doppler-limited spectra of the CO stretch fundamental of CD3OH

Abstract Doppler-limited linewidth diode laser spectra of the low- J P and R branches of the ν 4 band (CO stretch) of CD 3 OH were recorded and analyzed. Hindered internal rotation and molecular asymmetry are handled by exact matrix diagonalization. Fermi resonance between ν 4 and the τ = 1, n = 3 and n = 4 torsional levels of the ground vibration state was found to be responsible for several anomalous spectral features. Direct LMS fitting of the data to a set of 11 excited-state parameters lead to the assignment of 160 lines with a rms error of ±0.00088 cm −1 .

Fourier transform IR spectroscopic observation of propylene ozonide in the gas phase reaction of ozone—cis-2-butene—formaldehyde

Abstract IR spectroscopic evidence has been found for the gas phase formation of propylene ozonide via the homogeneous bimolecular reaction of the cis-2-butene ozonolysis intermediate with formaldehyde.

Sub-Doppler laser-Stark and high-resolution Fourier transform spectroscopy of the ν3 band of formic acid

Abstract The 5.6-μm band of HCOOH, which is the strong carbonyl stretch mode, is analyzed using a combination of sub-Doppler resolution laser-Stark data obtained with a CO laser and Fourier transform data obtained from a Bomem interferometer. The Fourier transform data, including 647 lines with J ′ ≤ 22 and K a ≤ 11, are fit with a Watson-type Hamiltonian to determine excited state constants. The Coriolis interactions with v 5+9 and v 6+9 , previously noted by Kuze et al. , are included in the analysis; the former by using an exact diagonalization technique, the latter via perturbation theory. Taking the molecular parameters from this fit, the laser-Stark data are then analyzed to give ground and excited state dipole moments, yielding the following results in Debyes: μ ″ a =1.4071(8) μ ″ b =0.227(10) μ ′ a =1.4353(9) μ ′ b =0.214(9), where the errors are 3σ estimates. The laser-Stark data are limited to J ′ ≤ 7 and give a ± 14 MHz fit to 191 lines.

An FIIR study of the mechanism for the gas phase reaction between HO2 radicals

Abstract Product studies of the self-reaction of HO2 were made using the FTIR method in the photolysis of Cl2 in the presence of H2 and O2 at 700 Torr total pressure and 298 K. The nature of the transition state involved in the formation of H2O2 via an H2O4 adduct was determined by an 18O-labeling technique, i.e. H16O2 + H18O2 → H216O2 + 18O2 and H218O2 + 16O2 but not H216O18O + 16O18O. An alternative reaction path 2HO2 → O3 + H2O was determined to be less than 0.1% of the total reaction of HO2.

FTIR studies of the kinetics and mechanism for the reaction of Cl atom with formaldehyde

Abstract Product studies were made with the FTIR method in the photolysis of mixtures containing Cl 2 and CH 2 O up to 1 torr each in I atm Ar. The formation of two principal products, HCl and HCClO, can be accounted for by the chain photochlorination of CH 2 O i.e., Cl 2 + hv → 2 Cl, Cl + CH 2 O → CHO + HCl, CHO + Cl 2 → HCClO + Cl. The rate constant for the ClCH 2 O reaction was determined from relative decay rates of CH 2 O and C 2 H 6 in the photolysis of Cl 2 CH 2 OC 2 H 6 mixtures. The value of k (Cl + CH 2 O/Cl + C 2 H 6 ) = 1.3 combined with the literature value of k (Cl + C 2 H 6 = 6 × 10 −11 cm 3 molecule −1 s −1 gives k (Cl + CH 2 O) = 7.8 × 10 −11 cm 3 molecule −1 s −1 at 298 ± 2 K.

FTIR spectroscopic observation of peroxyalkyl nitrates formed via ROO + NO2 → ROONO2

Abstract Kinetic and spectroscopic evidence has been obtained for the formation of peroxyalkyl nitrates via ROO + NO 2 → ROONO 2 (R = C n H 2 n +1 , n = 1–6) using CI-atom sensitized oxidation of alkane-NO 2 mixtures and a long path Fourier transform IR spectroscopic detection method.