Showing papers by "Lester Andrews published in 1990"
TL;DR: In this paper, the authors used both heated GaP and discharge of P 4 as sources of P 2 and isotopic ozone molecules to identify PO, PO 2, PO 2 −, PO 3, PO 4, P 2 O 4, PO 5 and PO 2−.
48 citations
TL;DR: In this article, an extensive infrared study of the photochemical reaction of germane and ozone has been performed in solid argon, and isotopic substitution at all positions and filtered photolysis provide a basis for identification of seven molecular product species.
Abstract: An extensive infrared study of the photochemical reaction of germane and ozone has been performed in solid argon. Isotopic substitution at all positions and filtered photolysis provide a basis for identification of seven new molecular product species. Germanone (H{sub 2}GeO), the germylene-water complex (H{sub 2}O-GeH{sub 2}), and hydroxygermylene (HGeOH) appeared on red photolysis and gave way to germanic acid ((HO){sub 2}GeO), its peroxo isomer (H(O{sub 2})GeOH), germanium oxide (GeO), and germanol (H{sub 3}GeOH) with ultraviolet photolysis.
43 citations
TL;DR: In this article, the electrically based molecular mechanics for clusters (MMC) approach has been applied to complexes of ammonia, including the ammonia dimer, trimer, and tetramer as well as mixed, binary complexes with hydrogen, water, hydrogen fluoride, and hydrogen cyanide.
Abstract: The electrically based molecular mechanics for clusters (MMC) approach has been applied to complexes of ammonia, including the ammonia dimer, trimer, and tetramer as well as mixed, binary complexes with hydrogen, water, hydrogen fluoride, and hydrogen cyanide. The MMC approach is designed for the generation of potential energy surfaces for weakly interacting assemblies, and equilibrium structures, stabilities, dipole moments, and harmonic frequencies for the intermolecular vibrational modes are obtained directly. This information is reported for the ammonia clusters that were studied and serves to characterize the nature of ammonia’s weak interactions. Generally, the good comparison with available spectroscopic data indicates that the weak bonding of ammonia is principally a consequence of its electrical properties and its shape. The trimer and tetramer are found to be symmetric, cyclic structures and the relative orientations of a pair of ammonias progress smoothly from the dimer to the trimer to the tet...
38 citations
TL;DR: In this paper, the Townsend discharge chemical ionization source has been used for matrix infrared studies of anions in the argon-N{sub 2}O system, including neutral products.
Abstract: A Townsend discharge chemical ionization source has been used for matrix infrared studies of anions in the argon-N{sub 2}O system. In addition to neutral products, the NO{sup {minus}}, NO{sub 2}{sup {minus}}, (NO){sub 2}{sup {minus}}, and O{sub 3}{sup {minus}} anions have also been isolated. Filtered visible photolysis shows different behaviors for these anions. The two isomers NNO{sub 2}{sup {minus}} and (NO){sub 2}{sup {minus}} have been identified by isotopic substitution and characterized by different {sup 15}N and {sup 18}O isotopic shifts and different structures. These matrix isolation experiments provide structural information on two different N{sub 2}O{sub 2}{sup {minus}} stoichiometry anions observed in mass spectroscopy experiments.
35 citations
TL;DR: In this article, photolysis of Ar/HCN/O{sub 3} samples with the full mercury arc produced the O-HCN hydrogen-bonded complex and HNCO as primary products and (HNCO)-sub 2 as a secondary product.
Abstract: Codeposition of argon-diluted samples of O{sub 3} and HCN produced a unique 1:1 O{sub 3}-HCN complex where the C{sub 2v} symmetry of O{sub 3} is retained and HCN appears to form weak hydrogen bonding interactions with both terminal atoms of O{sub 3}. Complexes with isotopic substitution at all atomic positions were studied. Photolysis of Ar/HCN/O{sub 3} samples with the full mercury arc produced the O-HCN hydrogen-bonded complex and HNCO as primary products and (HNCO){sub 2} as a secondary product.
32 citations
TL;DR: In this article, the authors used both heated GaP and discharge of P 4 from white phosphorus as sources of P 2 to identify P 4 O terminal and bridged isomers.
28 citations
TL;DR: In this article, a similar fraction of product absorptions was identified as phosphorus sulfides and diphosphorus sulfides (P 2 S 4, P 2 S 5 ) in the equilibrium vapor and in superheated vapor.
Abstract: Comparison with infrared spectra of solid P 4 S 10 and P 4 S 9 provides a basis for identification of molecular P 4 S 10 and P 4 S 9 , chich were isolated in comparable yields. A similar fraction of product absorptions is identified as phosphorus sulfides (PS, PS 2 ) and diphosphorus sulfides (P 2 S 4 , P 2 S 5 ), with P 2 S 5 being the major diphosphorus species in the equilibrium vapor and in superheated vapor. Photolysis of P 4 S 10 and O 3 mixtures produced new infrared absorptions for SO 2 and the terminal oxide P 4 S 9 O
22 citations
TL;DR: The P 4 /O 3 photolysis matrix system has been investigated in this paper by using dilute P 4 and a wide range of photolyisses wavelengths with red and ultraviolet wavelengths.
Abstract: The P 4 /O 3 matrix system has been reinvestigated by using dilute P 4 and a wide range of photolysis wavelengths With red photolysis the major product is terminal P 4 O; with ultraviolet photolysis absorptions for oxo-bridged tetrahedral P 4 O and cyclic planar P 4 O plus a series of oxo-bridged absorptions leading to P 4 O 6 and P 4 O 7 dominate Vacuum ultraviolet photolysis and glow discharge of P 4 O 6 produced an absorption for P 4 O 7 and three absorptions common to the P 4 /O 3 photolysis system, which are assigned to oxo-bridged P 4 O 5 , P 4 O 4 , and P 4 O 3
15 citations
TL;DR: In this paper, a photo-sensitive progression with 436-nm origin and 550±10-cm -1 vibrational interval maps the phtoelectron spectrum of P 4 +, which confirms this assignment.
Abstract: White phosphorus vapor (P 4 ) was passed through a short argon discharge and subjected to vacuum ultraviolet radiation during condensation with excess argon. Visible absorption spectra revealed two vibronic band systems. A photosensitive progression with 436-nm origin and 550±10-cm -1 vibrational interval maps the phtoelectron spectrum of P 4 + , which confirms this assignment
13 citations
7 citations
TL;DR: In this article, photolysis of the P 4 S 3 O 3 molecular complex in solid argon with red light produced two sets of new infrared absorptions including terminal PO and symmetric P-S-P stretching modes, which were assigned to structural isomers of P 4S 3 O with terminal oxygen at the apex and base phosphorus positions of P S 3.
Abstract: Photolysis of the P 4 S 3 --O 3 molecular complex in solid argon with red light produced two sets of new infrared absorptions including terminal PO and symmetric P-S-P stretching modes, which are assigned to structural isomers of P 4 S 3 O with terminal oxygen at the apex and base phosphorus positions of P 4 S 3 . Further ultraviolet photolysis produced evidence for oxo-bridged P 4 S 3 O and a secondary product, P 4 S 3 O 2
TL;DR: In this article, a chemical ionization source from mass spectrometry has been used with CCl 4, CHCl 3 and CH 2 Cl 2 /argon mixtures for matrix isolation spectroscopy in the IR and visible-near UV regions.
Abstract: A chemical ionization source from mass spectrometry has been used with CCl 4 , CHCl 3 and CH 2 Cl 2 /argon mixtures for matrix isolation spectroscopy in the IR and visible-near UV regions. The major product absorptions in both regions have been observed and assigned previously. The comparison of positive and negative ion operation is striking for CCl 4 ; the yields of CCl + 3 , CCl + 4 and Cl + 3 are increased and HCl − 2 is not produced in positive ion operation.