Browsing by Author "Glatthaar, Joerg"

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Advances in Use of p-H(2) as a Novel Host for Matrix IR Spectroscopy
(2010-08-01)
Bahou, Mohammed
;
Huang, Chiung-Wei
;
Huang, Ya-Ling
;
Glatthaar, Joerg
;
Lee, Yuan-Pern
A review of recent advances in IR spectroscopy using p-H(2) as a matrix host in our laboratory is presented. The softness of this novel p-H, matrix host not only makes high-resolution spectroscopy feasible but also provides new applications. Molecular motion, such as the rotation of C(2)H(4), internal rotation (torsion) of CH(3)OH, and rotation of CH(3)F about a single axis are characterized in this p-H, matrix. In contrast, no evidence for rotation of CH(3)I and CH(3) was found. The diminution of the cage effect leads to the possibility of production of free radicals via either photolysis in situ or bimolecular reactions of molecules with atoms that are produced in situ from their molecular precursors. Taking advantage of these unique features, we identified the IR spectrum of CH(3) produced from photolysis of CH(3)I and CH(3)S produced from photolysis of CH(3)SCH(3) and CH(3)SSCH(3). The reaction of Cl with CS(2) in solid p-H(2) yields ClSCS instead of ClCS(2). The reaction of Cl with HCOOH in solid p-H(2) yields only a complex, Cl center dot HCOOH, not HCl and HOCO. The presence of o-H(2) in trace proportions turned out to be an important factor in the interpretation of IR spectra of species embedded in solid p-H(2). Experimental techniques to minimize the amount of o-H(2) and to characterize its relative concentration with spectra of H(2)O center dot o-H(2) are discussed.
Advances in Use of p-H-2 as a Novel Host for Matrix IR Spectroscopy
(2010-08-01)
Bahou, Mohammed
;
Huang, Chiung-Wei
;
Huang, Ya-Ling
;
Glatthaar, Joerg
;
Lee, Yuan-Pern
A review of recent advances in IR spectroscopy using p-H-2 as a matrix host in our laboratory is presented. The softness of this novel p-H, matrix host not only makes high-resolution spectroscopy feasible but also provides new applications. Molecular motion, such as the rotation of C2H4, internal rotation (torsion) of CH3OH, and rotation of CH3F about a single axis are characterized in this p-H, matrix. In contrast, no evidence for rotation of CH3I and CH3 was found. The diminution of the cage effect leads to the possibility of production of free radicals via either photolysis in situ or bimolecular reactions of molecules with atoms that are produced in situ from their molecular precursors. Taking advantage of these unique features, we identified the IR spectrum of CH3 produced from photolysis of CH3I and CH3S produced from photolysis of CH3SCH3 and CH3SSCH3. The reaction of Cl with CS2 in solid p-H-2 yields ClSCS instead of ClCS2. The reaction of Cl with HCOOH in solid p-H-2 yields only a complex, Cl center dot HCOOH, not HCl and HOCO. The presence of o-H-2 in trace proportions turned out to be an important factor in the interpretation of IR spectra of species embedded in solid p-H-2. Experimental techniques to minimize the amount of o-H-2 and to characterize its relative concentration with spectra of H2O center dot o-H-2 are discussed.
Infrared absorption of GeNNO isolated in solid Ar
(2009-10-14)
Jiang, Zih-Min
;
Glatthaar, Joerg
;
Lee, Yuan-Pern
;
應用化學系
;
應用化學系分子科學碩博班
Codeposition of thermally generated atomic germanium vapor and nitrous oxide (N(2)O) in Ar onto a substrate at 11 K produced infrared absorption lines in several sets. The most prominent comprises intense lines at 1443.7, 1102.4, and 784.0 cm(-1) that become diminished upon irradiation with UV or visible light. These lines are attributed to v(1) (NO stretching), v(2) (NN+GeN stretching), and v(3) (NNO bending + NN stretching) modes of singlet GeNNO. Two additional weak features at 1238.1 and 2859.2 cm(-1) are assigned as v(3) + v(4) and 2v(1) of GeNNO, respectively. Weak doublet features at 1259.3/1255.5 and 1488.9/1486.4 cm(-1) are tentatively assigned to v(2) of triplet GeONN and v(1) of singlet cyc-Ge-eta(2) [NN(O)], respectively. Quantum-chemical calculations on the Ge + N(2)O system with density-functional theory (B3LYP /aug-cc-pVTZ) predict five stable structures: GeNNO (singlet and triplet), singlet cyc-Ge-eta(2) [NN(O)], triplet cyc-Ge-eta(2) (NNO), GeONN (singlet and triplet), and singlet GeNON. Vibrational wavenumbers, relative IR intensities, and (15)N-isotopic ratios for observed species are consistent with those computed. Irradiation of singlet GeNNO with lambda = 248 or 193 nm or lambda > 525 nm yields GeO. (C) 2009 American Institute of Physics. [doi:10.1063/1.3236384]