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Showing papers by "Lester Andrews published in 1975"


Journal ArticleDOI
TL;DR: In this paper, Proton and deuteron radiolysis of chlorine-containing samples produced HCl2X and DCl2x in high yields, and these species are probably anions.
Abstract: Argon matrix samples containing O2 and Cl2 have been bombarded with 2.0 keV protons and deuterons during condensation at 15°K. In the oxygen experiments, bands due to O3 and HO2 appeared. Of most interest is isolated O−3 at 804.3 cm−1. Deuteron radiolysis produced increased yields of the 644 cm−1 band which is confirmed as a DAr+n species. Proton and deuteron radiolysis of chlorine−containing samples produced HCl2x and DCl2x in high yields. Owing to the strong electron scavenging capability of chlorine, these species are probably anions.

49 citations



Journal ArticleDOI
TL;DR: In this article, the vibronic spectra of the M+O3− species were obtained with best resolution of up to 14 vibronic bands spaced 800-900 cm−1 apart for the lithium and sodium compounds.
Abstract: Matrix reactions of alkali metal atoms and ozone molecules at high dilution in inert gases produced a clear yellow film during condensation at 10–22 K on a sapphire plate which yielded vibronic spectra of the M+O3− species. Best resolution of up to 14 vibronic bands spaced 800–900 cm−1 apart was obtained for the lithium and sodium compounds. These bands formed a strong progression in ν1′ and the first six bands exhibited the presence of a weaker progression in ν2′. The band origin was located at 17 730 cm−1 for Li+16O3− and Li+18O3− in solid krypton. Harmonic and anharmonic vibrational constants were determined graphically for the excited electronic state.

46 citations


Journal ArticleDOI
TL;DR: Fluorescence spectra have been obtained from halogen molecules isolated in inert matrices at 15 K, leading to matrix values of ωe, ωexe, and T0, which are compared to the gas phase values as mentioned in this paper.

44 citations



Journal ArticleDOI
TL;DR: In this paper, a revised value of the ground state bending mode for CCl2 was obtained from higher-resolution spectra using more diluted samples and various laser exciting frequencies, and carbon-13 enriched samples confirm the assignments of the bands to progressions in the ground-state bending and symmetric stretching modes of CCL2.

39 citations



Journal ArticleDOI
TL;DR: In this article, the fluorescence and resonance Raman spectra were obtained from iodine monochloride and bromine chloride isolated in argon matrices and from BrCl in a krypton matrix.

29 citations


Journal ArticleDOI
TL;DR: In this paper, the infrared spectra of the reaction products of oxygen molecules and alkaline earth metal atoms in argon and nitrogen matrices have been recorded, and several bands of the metal oxide dimer were measured.
Abstract: Infrared spectra of the reaction products of oxygen molecules and alkaline earth metal atoms in argon and nitrogen matrices have been recorded. The ν2 interionic modes of barium, strontium, and calcium superoxides, MO2, have been located at 541, 474, and 498 cm−1, respectively, in nitrogen matrices. The metal oxide, MO, was isolated for each metal, and several bands of the metal oxide dimer were measured. Frequencies observed for the antisymmetric modes of (BaO)2 at 487 and 393 cm−1 indicate a D2h structure with an O−Ba−O angle of approximately 102°. Also, a band attributable to ν3 of a bent O−M−O metal dioxide species has been identified near 752 cm−1 for barium, 730 cm−1 for strontium, and 743 cm−1 for calcium, leading to a bond angle near 140° for all three species. A mechanism is proposed for the formation of the metal oxide from molecular oxygen, which includes MO2M and (MO)2 intermediates. It was also determined that nitrogen is much more effective as a matrix material in stabilizing ionic compounds...

28 citations


Journal ArticleDOI
TL;DR: In this paper, a 2.0 keV proton beam was used to irradiate chloroform and its deuterium and bromine analogs and the products trapped in an argon matrix at 15 °K.
Abstract: Matrix samples of chloroform and its deuterium and bromine analogs have been subjected to irradiation by a 2.0 keV proton beam during deposition, and the products trapped in an argon matrix at 15 °K. Several infrared absorptions have been observed and assigned to a number of new molecular species. Extremely photosensitive bands observed at 652, 621, 593, and 570 cm−1 have been assigned to the CHCl−3, CHCl2Br−, CHClBr−2, and CHBr−3 molecular anions, respectively. Absorptions at 998, 907, and 839 cm−1, which were decreased by operating an exposed bulb filament, have been attributed to the isolated cations CHCl+2, CHClBr+, and CHBr+2. Bands stable to the bulb filament at 1044, 988, and 898 cm−1 were assigned to the CHX+2 (X−) species and similar bands at 838, 795, and 735 cm−1 were assigned to the CHX2− anions. In addition, bands attributable to the species CX3, CX2CX3+(X−), CHX2, and HX−2, which have been identified previously, were observed here as well.

28 citations


Journal ArticleDOI
TL;DR: In this paper, the antisymmetric stretch ν3 of the HCl2− and DCl 2− anions in the M+HCl2+ and M+DCl2 − ion pairs was investigated.
Abstract: The matrix reactions of alkali metal chloride salts and HCl and DCl have been investigated in argon matrices, as well as the reaction of lithium metal with HCl and DCl. From each reaction product a single intense band was observed which has been assigned to the antisymmetric stretch ν3 of the HCl2− and DCl2− anions in the M+HCl2− and M+DCl2− ion pairs. Comparisons to literature spectra, in conjunction with quartic deuterium shifts, indicate that the anion has a linear, centrosymmetric geometry in the isolated ion pair. A rough estimate for the bond strength of the hydrogen bond in this anion is 18±2 kcal/mole. Further, comparison to the spectra of earlier workers indicates that bands previously asigned to the HCl2 radical are best reassigned to the isolated HCl2− anion.


Journal ArticleDOI
TL;DR: In this article, high intensity resonance Raman overtone progressions out to ν = 3, 14, 23, 24, 25, 17, and 3 have been observed with 457.9 nm, 476.5 nm, 514.0 nm, 530.2 nm, and 647.1 nm excitation respectively.
Abstract: High intensity resonance Raman overtone progressions out to ν = 3, 14, 23, 24, 25, 17, and 3 have been observed with 457.9 nm, 476.5 nm, 488.0 nm, 514.5 nm, 530.9 nm, 568.2 nm, and 647.1 nm excitation respectively, for monomeric iodine isolated in an argon matrix. The normalised intensities have been determined and plotted as excitation profiles for the overtones. There is substantial evidence indicating a resonance coupling not only with the 3∏Ou+ electronic state of I2, but also with the 1∏1u state. The following spectroscopic constants for matrix-isolated iodine have been calculated from the wavenumber data: ωe = (213.70±0.22) cm−1, ωeXe = (0.60±0.01) cm−1, and ωeYe = (−0.019±0.002) cm−1.



Journal ArticleDOI
TL;DR: In this article, the infrared spectra of the alkaline earth metal−ozone−nitrogen reaction mixtures were obtained, and the frequencies of the ALM oxide molecules were measured in nitrogen matrices.
Abstract: The infrared spectra of the alkaline earth metal−ozone−nitrogen reaction mixtures were obtained, and the frequencies of the alkaline earth metal oxide molecules were measured in nitrogen matrices. These were found to be 613, 620, and 707 cm−1 for BaO, SrO, and CaO, respectively; these assignments were confirmed by oxygen−18 substitution. From the known gas phase fundamentals and 1Σ ground electronic states of SrO and BaO, and the anticipated matrix shifts, the ground state of CaO was determined to be 1Σ owing to near agreement between the known 1Σ CaO gas phase fundamental and the CaO nitrogen matrix frequency. Ozone was found to be an excellent precursor for oxygen atom abstraction reactions in nitrogen matrices, while nitrous oxide was considerably less productive. The pattern of reactivity of the alkaline earth metals was determined to be decreasing from barium to magnesium, in agreement with earlier researchers and the work presented in the preceding paper in this series.



Journal ArticleDOI
TL;DR: In this article, the three most intense progressions are assigned to transitions from a common excited state to ground state levels (0 v 2 0), (1 v 2 1) and (1v 2 1).


Journal ArticleDOI
TL;DR: In this paper, it was shown that the species M + O 3 − and M + NO 2 − have been produced in matrix samples of alkali atoms, N 2 O and O 2 or NO by mercury arc photolysis.