Ab initio study of the isomerization and photodissociation of the C3H6O+ cation radicals

Mishima, Kenji; Hayashi, M.; Lin, Sheng Hsien

doi:10.1016/j.ijms.2004.08.003

Cited by 5 publications

(3 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recent photoionizantion and TPEPICO experiments yield 18.5 ± 0.5 kcal/mol for the energy difference between CH 3 COCH 3 • + and CH 3 CO + + CH 3 • at 0 K. This is slightly lower than the previous experimental value 19.8 ± 0.3 kcal/mol . A number of groups have used ab initio calculations to explore the potential energy surface for CH 3 COCH 3 • + . ,, The experimental values for CH 3 COCH 3 • + → CH 3 CO + + CH 3 • fall between the best calculated values, 17.7, 17.9, 21.1 and 20.6 kcal/mol for G2MP2, G3, CBS-QB3 and CBS-APNO, respectively. The best estimates for the keto to enol isomerization barrier CH 3 COCH 3 • + at 0 K are 36.0, 36.6, 35.8 and 34.7 kcal/mol for G2MP2, G3, CBS-QB3 and CBS-APNO, respectively.…”

Section: Introductionmentioning

confidence: 79%

“…A number of groups have used ab initio calculations to explore the potential energy surface for CH 3 COCH 3 • + . ,, The experimental values for CH 3 COCH 3 • + → CH 3 CO + + CH 3 • fall between the best calculated values, 17.7, 17.9, 21.1 and 20.6 kcal/mol for G2MP2, G3, CBS-QB3 and CBS-APNO, respectively. The best estimates for the keto to enol isomerization barrier CH 3 COCH 3 • + at 0 K are 36.0, 36.6, 35.8 and 34.7 kcal/mol for G2MP2, G3, CBS-QB3 and CBS-APNO, respectively.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dissociation of Acetone Radical Cation (CH₃COCH₃^+· → CH₃CO⁺ + CH₃^·): An Ab Initio Direct Classical Trajectory Study of the Energy Dependence of the Branching Ratio

Zhou

Schlegel

2008

J. Phys. Chem. A

View full text Add to dashboard Cite

We have investigated the photophysics of the acetone radical cation in the vacuum ultraviolet energy region by multiphoton ionization combined with time-of-flight mass spectrometry in a cluster beam. We have found that the loss of methyl radical from the acetone radical cations is remarkably suppressed at 10.5 eV when they are solvated by a few neutral acetone molecules. The cluster ion mass spectra obtained by nanosecond and picosecond laser pulses reveal that there are intermolecular processes, occurring in several tens of picoseconds, which are responsible for the survival of the acetone cations in clusters. This remarkable solvation effect on the yield of the methyl radical loss from the acetone cation can be rationalized by the intracluster vibrational energy redistribution and the self-catalyzed enolization which compete with the methyl radical loss process.

show abstract

Section: Introductionmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Dissociation of Acetone Radical Cation (CH₃COCH₃^+· → CH₃CO⁺ + CH₃^·): An Ab Initio Direct Classical Trajectory Study of the Energy Dependence of the Branching Ratio

Zhou

Schlegel

2008

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…Before closing, it should be mentioned that the channels of reactions 1a and 2a have been studied theoretically with the MP2(Full) method using a number of basis sets by Anand and Schlegel . In addition, these same two reactions have also been studied by Lin et al using the Gaussian-2 method …”

Section: Resultsmentioning

confidence: 99%

A Vacuum Ultraviolet Photoionization Mass Spectrometric Study of Acetone

Wei¹,

Yang²,

Huang³

et al. 2005

J. Phys. Chem. A

View full text Add to dashboard Cite

The photoionization and dissociative photoionization of acetone have been studied at the photon energy range of 8-20 eV. Photoionization efficiency spectra for ions CH3COCH3+, CH3+, C2H3+, C3H3+, C3H5+, CH(2-)CO+, CH3CO+, C3H4O+, and CH3COCH2+ have been measured. In addition, the energetics of the dissociative photoionization has been examined by ab initio Gaussian-3 (G3) calculations. The computational results are useful in establishing the dissociation channels near the ionization thresholds. With the help of G3 results, the dissociation channels for the formation of the fragment ions CH3CO+, CH2CO+, CH3+, C3H3+, and CH3COCH2+ have been established. The G3 results are in fair to excellent agreement with the experimental data.

show abstract

Cyanomethylidyne: A Reactive Carbyne Radical

Wang

Sun

2006

ChemPhysChem

View full text Add to dashboard Cite

The cyanomethylidyne radical (CCN) has been a long-standing subject of extensive structural and spectroscopic studies. However, its chemical reactivity has received rather little attention. Recently, we studied the reaction of CCN with the simplest alkane, CH4, which follows a mechanism of carbyne insertion-dissociation rather than that of direct H abstraction proposed by a recent experimental study. However, we are aware that alkanes like CH4 bear no electron lone pairs and thus are not ideal diagnostic molecules for distinguishing between the carbyne-insertion and H-abstraction mechanisms. Hence, we chose a series of sigma-bonded molecules HX (X=OH, NH2, and F) which bear electron lone pairs and are better diagnostics for carbyne-insertion behavior. The new results at the CCSD(T)/6-311+G(2df,p)//B3LYP/6-311G(d,p)+ZPVE, CCSD(T)/aug-cc-pVTZ//B3LYP/6-311G(d,p)+ZPVE, G2M(CC1), and MC-QCISD//B3LYP/6-31G(d)+ZPVE levels definitively confirm the carbyne-insertion behavior of the CCN radical towards HX. In addition, we make the first attempt to understand the reactivity of the CCN radical toward pi-bonded molecules, using the CCN+C2H2 model reaction. This reaction involves carbenoid addition to the C[triple chemical bond]C bond without a potential-energy barrier to form a C3 three-membered cyclic intermediate followed by H extrusion. Therefore, the reactions of CCN with both sigma- and pi-bonded molecules conclusively show that CCN is a reactive carbyne radical and may be more reactive than the well-known CN radical. Future experimental studies, especially on product characterization, are strongly desired to test our proposed carbyne mechanism. The studied reactions of CCN with CH4, NH3, H2O, and C2H2 could be of interest to combustion science and astrophysics, and they could provide efficient routes to form novel cyano-containing molecules in interstellar space.

show abstract

Ab initio study of the isomerization and photodissociation of the C3H6O+ cation radicals

Cited by 5 publications

References 50 publications

Dissociation of Acetone Radical Cation (CH₃COCH₃^+· → CH₃CO⁺ + CH₃^·): An Ab Initio Direct Classical Trajectory Study of the Energy Dependence of the Branching Ratio

Dissociation of Acetone Radical Cation (CH₃COCH₃^+· → CH₃CO⁺ + CH₃^·): An Ab Initio Direct Classical Trajectory Study of the Energy Dependence of the Branching Ratio

A Vacuum Ultraviolet Photoionization Mass Spectrometric Study of Acetone

Cyanomethylidyne: A Reactive Carbyne Radical

Contact Info

Product

Resources

About

Ab initio study of the isomerization and photodissociation of the C3H6O+ cation radicals

Cited by 5 publications

References 50 publications

Dissociation of Acetone Radical Cation (CH3COCH3+· → CH3CO+ + CH3·): An Ab Initio Direct Classical Trajectory Study of the Energy Dependence of the Branching Ratio

Dissociation of Acetone Radical Cation (CH3COCH3+· → CH3CO+ + CH3·): An Ab Initio Direct Classical Trajectory Study of the Energy Dependence of the Branching Ratio

A Vacuum Ultraviolet Photoionization Mass Spectrometric Study of Acetone

Cyanomethylidyne: A Reactive Carbyne Radical

Contact Info

Product

Resources

About

Dissociation of Acetone Radical Cation (CH₃COCH₃^+· → CH₃CO⁺ + CH₃^·): An Ab Initio Direct Classical Trajectory Study of the Energy Dependence of the Branching Ratio

Dissociation of Acetone Radical Cation (CH₃COCH₃^+· → CH₃CO⁺ + CH₃^·): An Ab Initio Direct Classical Trajectory Study of the Energy Dependence of the Branching Ratio