A study of the vacuum pyrolysis of 11 -oxatricyclo[6.2.1.02,7]undeca-2,9-diene. The HeI ultraviolet photoelectron spectrum of 1,2-cyclohexadiene

1996 ◽  
Vol 74 (10) ◽  
pp. 1903-1905 ◽  
Author(s):  
Nick Henry Werstiuk ◽  
Chandra Deo Roy ◽  
Jiangong Ma
Keyword(s):  
Heat Source ◽  
Ab Initio ◽  
Key Words ◽  
Molecular Orbital ◽  
Photoelectron Spectrum ◽  
Equilibrium Structure ◽  
Ionization Energies ◽  
Vacuum Pyrolysis ◽  
Laser Apparatus ◽  
Ab Initio Hf

A newly developed ultraviolet photoelectron spectrometer – CO2, laser apparatus that utilizes a 50-watt CW CO2, laser as a directed heat source is used to study the vacuum pyrolysis of 11-oxatricyclo[6.2.1.02,7]undeca-2,9-diene (4). We report the HeI photoelectron spectrum of the strained cyclic allene 1,2-cyclohexadiene (1) that correlates with the HAM/3 ionization energies calculated with the optimized C2, equilibrium structure obtained with AM1 and the molecular orbital energies of the optimized C2, equilibrium structure calculated at the ab initio HF/6-31G** level of theory. Key words: 11-oxatricyclo[6.2.1.02,7]undeca-2,9-diene, vacuum pyrolysis, HeI ultraviolet photoelectron spectrum, 1,2-cyclohexadiene.

A study of the vacuum pyrolysis of 1,2,3-benzotriazines. The Hel ultraviolet photoelectron spectra of benzazete and o-benzyne

1995 ◽  
Vol 73 (1) ◽  
pp. 146-149 ◽  
Author(s):  
Nick Henry Werstiuk ◽  
Chandra Deo Roy ◽  
Jiangong Ma
Keyword(s):  
Heat Source ◽  
Ab Initio ◽  
Photoelectron Spectra ◽  
Equilibrium Geometry ◽  
Ionization Energies ◽  
Vacuum Pyrolysis ◽  
Ab Initio Hf

A CW CO2 laser is used as a directed heat source to carry out the vacuum pyrolysis of 1,2,3-benzo-triazine (1a) and 4-methyl-1,2,3-benzotriazine (1b). We report the first HeI photoelectron (pe) spectrum of benzazete (2a), which correlates with ionization energies calculated with HAM/3 using an equilibrium geometry obtained at the ab initio HF/6-31G** level of the theory. The pe spectrum of o-benzyne (3) obtained in this study correlates with the spectrum published by Zhang and Chen, but not with the spectra reported in two earlier publications. Keywords: 1,2,3-benzotriazines, vacuum pyrolysis, HeI ultraviolet photoelectron spectra, benzazete, benzyne.

The Photoelectron Spectrum of 1-Bromonortricyclene

1985 ◽  
Vol 38 (1) ◽  
pp. 69 ◽  
Author(s):  
EW Della ◽  
PE Pigou ◽  
MK Livett ◽  
JB Peel
Keyword(s):  
Energy Range ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Density Of States ◽  
Ionization Energy ◽  
Photoelectron Spectrum ◽  
Valence Electron ◽  
Alkyl Halide ◽  
High Density ◽  
Molecular Orbital Calculations

The He I photoelectron spectrum of 1-bromotricyclo[2.2.1.02.6] heptane (1- bromonortricyclene ) is compared with that of the parent alkane . Extensive conjugation between bromine and alkane orbitals in the low ionization-energy range produces a complex band pattern which is adequately described by ab initio valence-electron molecular orbital calculations. Consequently 1-bromo-nortricyclene presents a rare example of an alkyl halide in which the halogen character is neither highly localized nor smeared over a high density of states.

Molecular Orbital Calculations of Cu-Halides

1981 ◽  
Vol 36 (10) ◽  
pp. 1095-1099 ◽  
Author(s):  
H. Itoh
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Energy Levels ◽  
Basis Set ◽  
Orbital Energy ◽  
Ionic Character ◽  
Molecular Orbital Calculations ◽  
Ab Initio Hf ◽  
Mo Theory

An ab initio HF MO theory is applied to CuX, CuX2 (X = F and Cl) and (CuCl)3 . Although the detailed sequence of energy levels depends upon the basis set used, high-lying orbital energy levels have largely halogen p-like character, whereas low-lying orbital energy levels have largely Cu 3 d-like character. This is in agreement with the chemical intuition of a highly ionic character of these compounds.

Beryllocene, (C5H5)2Be. The He(I) photoelectron spectrum and ab initio molecular orbital calculations

1979 ◽  
Vol 170 (3) ◽  
pp. 285-292 ◽  
Author(s):  
Rolf Gleiter ◽  
Michael C. Böhm ◽  
Arne Haaland ◽  
Ragnar Johansen ◽  
Janusz Lusztyk
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Photoelectron Spectrum ◽  
Molecular Orbital Calculations

A study of the vacuum pyrolysis of 4-diazoisothiochroman-3-one with Hel ultraviolet photoelectron spectroscopy

1996 ◽  
Vol 74 (12) ◽  
pp. 2536-2539 ◽  
Author(s):  
N.H. Werstiuk ◽  
J. Ma ◽  
C.D. Roy ◽  
A.J. Kresge ◽  
E.A. Jefferson
Keyword(s):  
Heat Source ◽  
Ab Initio ◽  
Photoelectron Spectroscopy ◽  
Laser Power ◽  
Activation Enthalpy ◽  
Power Level ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
Wolff Rearrangement ◽  
Vacuum Pyrolysis ◽  
New Compounds

A newly developed ultraviolet photoelectron spectrometer apparatus that utilizes a tunable 50 W CW CO2 laser as a directed heat source is used to study the vacuum pyrolysis of 4-diazoisothiochroman-3-one (1a). Analysis of the pyrolysate with ultraviolet photoelectron spectroscopy shows that 1a undergoes a facile pyrolysis at a laser power level of less than 26 W, yielding two new compounds: thiaketene 3a, the product of a Wolff rearrangement, and benzocyclobutenthione (6a), which can be derived from thiacarbene 4a, the decarbonylation product of 3a. Activation enthalpies/energies calculated at the AM1 and ab initio levels of theory indicate that, unlike the case of 4-diazoisochroman-3-one (1b), the Wolff rearrangement of the incipient carbene may be concerted with loss of nitrogen from 1a. The activation enthalpy/energy calculated for the decarbonylation of 3a is significantly higher (AM1, 20.5 kcal/mol; RHF/6-31G(d), 11.7 kcal/mol; MP2(full)//RHF/6-31G(d), 14.3 kcal/mol) than the activation enthalpy/energy for the decarbonylation of 3b. This result is in keeping with the fact that we detect 3a, but 3b is not found in detectable amounts in the pyrolysate of 1b. Key words: vacuum pyrolysis, 4-diazoisothiochroman-3-one, HeI ultraviolet photoelectron spectroscopy, AM1 and ab initio calculations.

Adaptation of the Gelius intensity model in semiempirical HAM/3 molecular orbital calculations of valence photoelectron spectra excited by X-ray radiation

1985 ◽  
Vol 63 (7) ◽  
pp. 2007-2011 ◽  
Author(s):  
Delano P. Chong
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Cross Sections ◽  
Present Method ◽  
Photoelectron Spectra ◽  
Molecular Orbital Calculations ◽  
Ionization Energies ◽  
X Ray ◽  
Hartree Fock ◽  
Intensity Model

The Gelius intensity model has been adapted in the semiempirical HAM/3 method to calculate the valence ionization energies and intensities in XPS. Both semiempirical and àb initio Hartree–Fock–Slater atomic photoionization cross-sections can be used. Results presented for C2H2, C2H4, N2, H2O, CH3OH, and CH2F2 demonstrate that the present method can facilitate the interpretation of experimental XPS.

Pyrolysis of 2-methoxy-5,5-dimethyl-2-methylthio- 2,5-dihydro[1,3,4]oxadiazole studied with photoelectron spectroscopy and DFT calculations — He(I) photoelectron spectrum of methoxy(methylthio)carbene

2006 ◽  
Vol 84 (4) ◽  
pp. 546-554 ◽  
Author(s):  
N H Werstiuk ◽  
A Klys ◽  
J Warkentin
Keyword(s):  
Heat Source ◽  
Dft Calculations ◽  
Key Words ◽  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Photoelectron Spectrum ◽  
Calculated Data ◽  
Experimental Results ◽  
Photoelectron Spectra ◽  
Key Words 2

Gas-phase pyrolysis of 2-methoxy-2-methylsulfanyl-5,5-dimethyl-2,5-dihydro[1,3,4]oxadiazole (1) (also known as 2-methoxy-5,5-dimethyl-2-methylthio-2,5-dihydro[1,3,4]oxadiazole and 2-methoxy-2-methylthio-5,5-dimethyl-Δ3-l,3,4-oxadiazoline) in the source of an UV photoelectron spectrometer, by means of a CW CO2 laser as directed heat source, gave a photoelectron (PE) spectrum that included ionization bands belonging to acetone and methoxy(methylthio)carbene (3). Photoelectron spectra of authentic samples of (E)-1,2-dimethoxy-1,2-dimethyl thioethene (4), (Z)-1,2-dimethoxy-1,2-dimethylthioethene (5), S-methyl thioethanoate (6), and O-methyl ethanethioate (7), which can be derived by dimerization and rearrangement of the carbene, established that these compounds are not present in the pyrolysate. DFT calculations at the B3PW91/6-31+G(d,p) level and simulation of PE spectra at the B3LYP/6-31+G(d,p) level were instrumental in the interpretation of the experimental results. From the available experimental and calculated data, 3 is formed in a Sickle conformation upon pyrolysis of 1. Transition states for the rearrangement of 3 were examined with QTAIM. Key words: 2-methoxy-5,5-dimethyl-2-methylthio-2,5-dihydro[1,3,4]oxadiazole, pyrolysis, He(I) photoelectron spectroscopy, methoxy(methylthio)carbene, DFT calculations, QTAIM.

Sign in / Sign up

Export Citation Format

Share Document