High-Resolution Spectroscopy of Solid Hydrogen

Oka, T.

doi:10.1146/annurev.pc.44.100193.001503

Cited by 163 publications

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“…One successful approach to overcoming the optical scattering problem and obtaining very long optical pathlengths has been to prepare pH 2 solids by gas condensation within an enclosed cell held at» 0.5 of the pH 2 triple point temperature 18 ' 21 (T^CpHj) = 13.8 K; T cell is typically 7 to 8 K). Transparent doped and pure pH 2 solids up to 11.5 cm thick have been prepared in this manner and characterized spectroscopically.…”

Section: Solid Molecular Hydrogens As Matrix Hostsmentioning

confidence: 99%

“…Transparent doped and pure pH 2 solids up to 11.5 cm thick have been prepared in this manner and characterized spectroscopically. 18 Similar techniques for condensing other matrix host gases in semi-enclosed cells also produce large transparent solids. 23 ' 26 Unfortunately, deposition at temperatures above « 0.3 T^ requires that dopant concentrations be kept well below « 100 PPM to avoid extensive aggregation and clustering.…”

Section: Solid Molecular Hydrogens As Matrix Hostsmentioning

confidence: 99%

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Ortho/para hydrogen converter for rapid deposition matrix isolation spectroscopy

Tam

Fajardo

1999

Review of Scientific Instruments

125

109

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We describe the construction and operation of a catalyst-bed type device for precooling and equilibrating the ortho/para composition of a hydrogen gas flow. We use this device to vapor deposit millimeters thick cryogenic parahydrogen (pH2) solids which are remarkably transparent [M. E. Fajardo and S. Tam, J. Chem. Phys. 108, 4237 (1998)]. Infrared absorption spectra of solids deposited at pH2 flow rates up to 290 mmol/h (solid thickness growth rates up to 75 μm/min indicate a residual orthohydrogen (oH2) content of less than 0.01%. Gas phase thermal conductivity measurements indicate a residual oH2 content of 0(−0+5)% for flow rates up to 1.9 mol/h. These pH2 solids can be doped readily by simple codeposition of various impurities produced by any of the numerous dopant sources developed in previous matrix isolation spectroscopy (MIS) studies. The long achievable path lengths, and the desirable properties of pH2 as a matrix host, will enable significant new fundamental and practical applications for MIS.

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Section: Solid Molecular Hydrogens As Matrix Hostsmentioning

confidence: 99%

Section: Solid Molecular Hydrogens As Matrix Hostsmentioning

confidence: 99%

Ortho/para hydrogen converter for rapid deposition matrix isolation spectroscopy

Tam

Fajardo

1999

Review of Scientific Instruments

125

109

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“…The broadness of the linewidths wipes out most spectral information that might give us detailed information on intermolecular interactions and other properties of condensed phases. However, an exception to this generalization was recently found for solid hydrogen crystals [1][2][3]. Optical transitions of hydrogen crystals in the infrared spectral region are, surprisingly, as narrow as 4 MHz (= 0.00013 cm -1 ) [4].…”

Section: Introductionmentioning

confidence: 92%

Quantum property of solid hydrogen as revealed by high-resolution laser spectroscopy

Katsuki

Fushitani

Momose

2003

Low Temperature Physics

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Pure vibrational overtone transitions of solid parahydrogen were studied using high-resolution laser spectroscopy. Extremely narrow spectral linewidth (~20 MHz) allowed us to observe rich spectral structure that originates in subtle intermolecular interactions in the crystal. It was found that anisotropy of the distribution of zero-point lattice vibration of hydrogen molecules perturbs the energy levels of the vibrationally excited states significantly. Large amplitude of the zero-point lattice vibration being an intrinsic nature of quantum solids, was directly observed from the present high-resolution spectroscopy. The first observation of a pure vibrational overtone transition of solid orthodeuterium is also discussed.

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“…The use of pH2 solids with very low residual orthohydrogen (oH2) concentrations as matrix hosts for chemically interesting dopants originated in the Oka laboratory in Chicago, and has advanced in collaboration with Shida and Momose and coworkers in Kyoto (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24). These authors have reviewed in detail the unique properties of solid pH2 as amatrix host, including the preservation of the spherical nature of the ground state (v = 0, J = 0) pH 2 molecules in the solid phase, and the resulting advantages to high resolution rovibrational spectroscopy (14,16).…”

Section: Introductionmentioning

confidence: 99%

“…These authors have reviewed in detail the unique properties of solid pH2 as amatrix host, including the preservation of the spherical nature of the ground state (v = 0, J = 0) pH 2 molecules in the solid phase, and the resulting advantages to high resolution rovibrational spectroscopy (14,16). Most of the samples utilized in these pioneering studies were produced by condensation of a room temperature dopant/pH 2 gas mixture in an enclosed cell held near 2 the pH 2 triple point temperature of Ttp = 13.8 K. This approach results in beautifully transparent, centimeters-long, polycrystalline samples which are stable over a relatively broad temperature range.…”

Section: Introductionmentioning

confidence: 99%

Matrix isolation spectroscopy of H2O, D2O, and HDO in solid parahydrogen

FAJARDO¹

2004

Journal of Molecular Structure

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Public reporting burlenror this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information ABSTRACTWe present infrared (IR) absorption spectra over the 800-7800 cm"1 region of cryogenic parahydrogen (pH 2 ) solids doped with H20, D 2 0 and HDO molecules. Analysis of the rovibrational spectra of the isolated H 2 0, D 2 0 and HDO monomers reveals their existence as very slightly hindered rotors, typically showing only 2 to 5 % reductions in rotational constants relative to the gas phase. The nuclear spin conversion (NSC) of metastable J = 1 ortho-H 2 0 (oH20) and para-D 2 0 (pD 2 0) molecules follow first order kinetics, with single exponential decay lifetimes at T = 2.4 K of 1900±100 s, and 860±50 s, respectively. We report without discussion some absorptions of water clusters produced during sample annealing. We report and assign a number of absorptions to oH2-water pairs or "complexes." The main features of the oH 2 -H 2 0 and oH 2 -D 2 0 spectra are explained qualitatively by assuming a semi-rigid C 2 , structure with the oH2 acting as a proton donor to the 0 atom. Surprisingly, NSC of oH 2 -water complexes proceeds at very nearly the same rate as for the corresponding water monomer. We report unassigned spectra of larger (oH2)n-water clusters, and the even more surprising observation of the prolonged survival of 01-20 and pD 2 0 molecules clustered with several o0-2 molecules. We report and assign a number of water dopant-induced IR absorption features of the pH2 host, along with cooperative water-pH 2 transitions in which the vibrational excitation of the pH2 solid is accompanied by a pure rotational transition of the water dopant.

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High-Resolution Spectroscopy of Solid Hydrogen

Cited by 163 publications

References 0 publications

Ortho/para hydrogen converter for rapid deposition matrix isolation spectroscopy

Ortho/para hydrogen converter for rapid deposition matrix isolation spectroscopy

Quantum property of solid hydrogen as revealed by high-resolution laser spectroscopy

Matrix isolation spectroscopy of H2O, D2O, and HDO in solid parahydrogen

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