Photodissociation dynamics of vibrationally excited CH2Cl2 molecules

Marom, Ran; Golan, Amir; Rosenwaks, Salman; Bar, Ilana

doi:10.1016/j.cplett.2003.07.012

Cited by 15 publications

(8 citation statements)

References 34 publications

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“…Similar bond dissociation energies have been reported for SiCl 4 and CH 2 Cl 2 in the literature (about 460, 410, and 334 kJ•mol -1 , for Si-Cl, C-H and C-Cl bonds, respectively, ranging from 4.8 to 3.5 eV), [30][31][32] so that similar deposition rates of carbon and silicon under EB irradiation are expected.…”

Section: Resultssupporting

confidence: 77%

A Study of Electron Beam Induced Deposition and Nano Device Fabrication Using Liquid Cell TEM Technology

et al. 2014

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SiC x nano dots and nano wires with sizes from 60 nm to approximately 2 μm were fabricated using liquid cell transmission electron microscope (TEM) technology. A SiCl 4 in CH 2 Cl 2 solution was sealed between two pieces of Si 3 N 4 window grids in an in situ TEM liquid cell. Focused 200 keV electron beams were used to bombard the sealed precursors, which caused decomposition of the precursor materials, and deposition of the nano materials on the Si 3 N 4 window substrates. The size of nano dots increased with beam exposure time, following an approximately exponential relationship with the beam doses. Secondary electrons are attributed as the primary sources for the Si and C reduction. A nano device was formed from a deposited nano wire, with its electrical property characterized.

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Section: Resultssupporting

confidence: 77%

A Study of Electron Beam Induced Deposition and Nano Device Fabrication Using Liquid Cell TEM Technology

et al. 2014

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“…The finestructure branching ratios of Cl atoms produced from the vibrationally meditated photodissociation of CH 2 Cl 2 and CHF 2 Cl molecules with near-infrared (∼1151 nm) and ultraviolet (∼235 nm) laser light have been studied. 34,35 The photoabsorption band of CFCs and chlorinated hydrocarbons around 193.3 nm has no structure, indicating that the excited state is dissociative. The absorption of a 193.3 nm photon by chloromethanes leads to an excitation to the first absorption band which originates from a 3pπ f σ*(C-Cl) transition within the valence shell, where 3pπ is the lone pair orbital of Cl and σ* is the antibonding orbital of the C-Cl bond.…”

Section: Resultsmentioning

confidence: 99%

Quantum Yields for Cl(²P_j) Atom Formation from the Photolysis of Chlorofluorocarbons and Chlorinated Hydrocarbons at 193.3 nm

2005

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Cl(2P(3/2)) and Cl*(2P(1/2)) atoms produced from the photodissociation of chlorofluorocarbons (CFCs) and chlorinated hydrocarbons at 193.3 nm have been detected quantitatively by a technique of vacuum ultraviolet laser-induced fluorescence (VUV-LIF) spectroscopy at 135.2 and 134.7 nm for j = 1/2 and 3/2, respectively. The quantum yields for total Cl-atom formation in the 193.3 nm photolysis at 295 +/- 2 K have been determined to be 1.03 +/- 0.09, 1.01 +/- 0.08, 1.03 +/- 0.08, 1.03 +/- 0.10, 1.41 +/- 0.14, 1.02 +/- 0.08, and 0.98 +/- 0.08 for CF2Cl2, CFCl3, CH2Cl2, CHCl3, CCl4, CHFCl2, and CCl3CF3, respectively. Those results suggest that the single C-Cl bond rupture always occurs in the photolysis of these molecules except for CCl4. Formation of two Cl atoms partly takes place in the photodissociation of CCl4. The quantum yields for total Cl-atom formation in the 193.3 nm photolysis of CHBr2Cl and CHBrClCF3 are 0.27 +/- 0.02 and 0.28 +/- 0.02, respectively, which suggests that the C-Br bond rupture is a main channel in the photodissociation processes. The branching ratios between the spin-orbit states, Cl*(2P(1/2)) and Cl(2P(3/2)), have also been determined for the photodissociation of the chlorinated compounds at 193.3 nm. The UV photodissociation processes giving rise to formation of Cl(2P(j)) atoms from the chlorinated compounds studied here have been discussed.

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“…This indicates an excitation wavelength dependent mechanism. DCM is known to to dissociate in the VUV (due to a weak absorption extending to 240 nm) to form chlorine atoms and CH 2 Cl radical. , The absorption cross section of CH 2 Cl 2 at 193 nm is 3.35 × 10 –19 cm 2 molecule –1 ; ε = 900 M –1 cm –1 . The quantum yield of Cl atoms formation is 1.…”

Section: Discussionmentioning

confidence: 99%

“…DCM is known to to dissociate in the VUV (due to a weak absorption extending to 240 nm) to form chlorine atoms and CH 2 Cl radical. 46 Thus, in DCM it is possible to form molecules such as CDMAPA, CDMAPP, PCMDMA, PDCMDMA, and PDMAT, as proposed. At this point the data are not extensive enough to permit a detailed mechanism.…”

Section: Assignmentmentioning

confidence: 99%

Solution Photochemistry of [p-(Dimethylamino)phenyl]pentazole (DMAPP) at 193 and 300 nm

Bazanov

Haas

2014

J. Phys. Chem. A

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The photochemistry of [p-(dimethylamino)phenyl]pentazole (DMAPP) at 193 nm and in the near UV is reported, with emphasis on the nature of the final stable products. The (dimethylamino)phenyl azide (DMAPA) is found as a major product in MeCN, but not in dichloromethane (DCM). (In this paper the acronyms DMAPP and DMAPA refer to the para isomers.) The photochemistry of DMAPA is also explored for comparison. The data obtained in MeCN solutions are consistent with the initial formation of the corresponding nitrene, but in DCM, different products are found, on the basis of NMR data. In the case of high reactant concentration in DCM (10(-2) M), quantitative conversion of DMAPP and DMAPA is observed, indicating a high quantum yield. In contrast, MeCN solutions react much more slowly. A radical-type chain reaction mechanism is proposed to account for this observation. At high dilution, DMAPP is completely converted to products in both solvents. Possible mechanisms accounting for these results are discussed.

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Photodissociation dynamics of vibrationally excited CH2Cl2 molecules

Cited by 15 publications

References 34 publications

A Study of Electron Beam Induced Deposition and Nano Device Fabrication Using Liquid Cell TEM Technology

A Study of Electron Beam Induced Deposition and Nano Device Fabrication Using Liquid Cell TEM Technology

Quantum Yields for Cl(²P_j) Atom Formation from the Photolysis of Chlorofluorocarbons and Chlorinated Hydrocarbons at 193.3 nm

Solution Photochemistry of [p-(Dimethylamino)phenyl]pentazole (DMAPP) at 193 and 300 nm

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Photodissociation dynamics of vibrationally excited CH2Cl2 molecules

Cited by 15 publications

References 34 publications

A Study of Electron Beam Induced Deposition and Nano Device Fabrication Using Liquid Cell TEM Technology

A Study of Electron Beam Induced Deposition and Nano Device Fabrication Using Liquid Cell TEM Technology

Quantum Yields for Cl(2Pj) Atom Formation from the Photolysis of Chlorofluorocarbons and Chlorinated Hydrocarbons at 193.3 nm

Solution Photochemistry of [p-(Dimethylamino)phenyl]pentazole (DMAPP) at 193 and 300 nm

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Quantum Yields for Cl(²P_j) Atom Formation from the Photolysis of Chlorofluorocarbons and Chlorinated Hydrocarbons at 193.3 nm