Nuclear spin relaxation of methane in solid xenon

Sugimoto, Tetsuya; Arakawa, Ichiro; Yamakawa, Koichiro

doi:10.1140/epjd/e2017-80564-0

Cited by 7 publications

(6 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Here, methane is in Phase II, in which six of the eight molecules in the unit cell are orientationally ordered, while the other two are virtually rotationally free. Both phases have been seen and identified before (see refs , and references cited therein). The emergence of additional features in the top traces is due to NSC and is explained in the later half of the paper.…”

Section: Results and Analysissupporting

confidence: 52%

“…Molecules with two or more than two hydrogen atoms, such as H 2 , H 2 CO, H 2 O, NH 3 , and CH 4 , can undergo a change of the nuclear spin, or nuclear spin conversion (NSC), while keeping the same parity of the wave function. , The case of CH 4 is particularly interesting because of the presence of three nuclear spin isomers; furthermore, the distribution of populations in the isomers can give clues to the origin and processing of CH 4 ice in comets . The nuclear spin conversion has not been observed in the gas phase and can be studied in laboratory time scales only in ices, whether in solid CH 4 or CH 4 embedded in rare-gas , or para-hydrogen matrices. , …”

Section: Introductionmentioning

confidence: 99%

“…There have been numerous studies of the NSC in CH 4 in noble gas matrices and in para-hydrogen matrices (see refs , and references cited therein). Several techniques were used to measure the NSC in solid CH 4 : nuclear magnetic resonance (NMR), thermal conductivity, neutron scattering, and infrared spectroscopy. ,, The requirement on the symmetry of the wave function pins rotational levels to nuclear spins.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Infrared Spectroscopic Study of Solid Methane: Nuclear Spin Conversion of Stable and Metastable Phases

Emtiaz

Toriello

et al. 2019

J. Phys. Chem. A

View full text Add to dashboard Cite

Infrared spectroscopy was employed to study thin films of solid methane at low temperatures. We report new measurements of temporal changes of infrared spectra of methane ice in the ν3 and ν4 bands due to nuclear spin conversion upon rapid cooling from 30 to 6.0–11.0 K. The relaxation rates of the nuclear spin were found to be a function of temperature. The activation energy associated with the relaxation has been determined over an extended temperature range. We also found a new metastable phase of methane ice upon deposition at T < 7 K. After the deposition at 6 K and annealed to a higher temperature, a phase transition from the metastable phase to a stable crystalline phase takes place. We found that the relaxation has different activation energies below and above 8.5 K. From a quantitative analysis of the ν3 and ν4 IR bands, we suggest that the metastable phase is a crystalline phase with a degree of orientational disorder between the two known stable solid phases.

show abstract

Section: Results and Analysissupporting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Infrared Spectroscopic Study of Solid Methane: Nuclear Spin Conversion of Stable and Metastable Phases

Emtiaz

Toriello

et al. 2019

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…[23][24][25][26][27][28][29][30][31][32][33][34][35][36] In order to better understand the particular matrix effects, specialized theoretical models have been derived for carbon dioxide 37 and methane. [38][39][40][41] However, these models are not readily transferable to other systems without further ado. On the other side, approaches for an efficient and accurate calculation of various host-guest combinations rely on approximations that limit the incorporation of different matrix effects and anharmonicity.…”

Section: Introductionmentioning

confidence: 99%

Decomposing anharmonicity and mode-coupling from matrix effects in the IR spectra of matrix-isolated carbon dioxide and methane

Dinu

Podewitz

Grothe

et al. 2020

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…In the present study, we show that matrix effects are not systematic, thus, not easily transferrable from one case to another. This investigation comprises widely studied MI-IR spectra of the monomeric species of water [3][4][5][6][7][8][9][10][11], carbon dioxide [12][13][14][15][16], methane [17][18][19][20][21][22][23], and methanol [24][25][26][27][28]. We refer to further in-depth historical accounts for water [29] as well as carbon dioxide and methane [30].…”

Section: Introductionmentioning

confidence: 99%

On the synergy of matrix-isolation infrared spectroscopy and vibrational configuration interaction computations

et al. 2020

View full text Add to dashboard Cite

The key feature of matrix-isolation infrared (MI-IR) spectroscopy is the isolation of single guest molecules in a host system at cryogenic conditions. The matrix mostly hinders rotation of the guest molecule, providing access to pure vibrational features. Vibrational self-consistent field (VSCF) and configuration interaction computations (VCI) on ab initio multimode potential energy surfaces (PES) give rise to anharmonic vibrational spectra. In a single-sourced combination of these experimental and computational approaches, we have established an iterative spectroscopic characterization procedure. The present article reviews the scope of this procedure by highlighting the strengths and limitations based on the examples of water, carbon dioxide, methane, methanol, and fluoroethane. An assessment of setups for the construction of the multimode PES on the example of methanol demonstrates that CCSD(T)-F12 level of theory is preferable to compute (a) accurate vibrational frequencies and (b) equilibrium or vibrationally averaged structural parameters. Our procedure has allowed us to uniquely assign unknown or disputed bands and enabled us to clarify problematic spectral regions that are crowded with combination bands and overtones. Besides spectroscopic assignment, the excellent agreement between theory and experiment paves the way to tackle questions of rather fundamental nature as to whether or not matrix effects are systematic, and it shows the limits of conventional notations used by spectroscopists.

show abstract

Nuclear spin relaxation of methane in solid xenon

Cited by 7 publications

References 26 publications

Infrared Spectroscopic Study of Solid Methane: Nuclear Spin Conversion of Stable and Metastable Phases

Infrared Spectroscopic Study of Solid Methane: Nuclear Spin Conversion of Stable and Metastable Phases

Decomposing anharmonicity and mode-coupling from matrix effects in the IR spectra of matrix-isolated carbon dioxide and methane

On the synergy of matrix-isolation infrared spectroscopy and vibrational configuration interaction computations

Contact Info

Product

Resources

About