dorsal/arxiv
View SchemaNuclear spin conversion in polyatomic molecules
| Authors | P. L. Chapovsky, L. J. F. Hermans |
|---|---|
| Categories | |
| ArXiv ID | physics/0204036 |
| URL | https://arxiv.org/abs/physics/0204036 |
| Journal | Preprint. Published in Annu. Rev. Phys. Chem. v.50, 315-345 (1999) |
Abstract
Except for ortho- and para-H2, very little is known about nuclear spin isomers (or spin modifications) of molecules. The main reason is the lack of practical enrichment techniques. Recently a few enrichment methods were developed, which opened up new possibilities in the field. These methods are briefly reviewed. Substantial progress in the field has been made by the introduction of Light-Induced Drift as a gas-phase separation tool. This is illustrated by extensive data on CH3F, which reveal that the gas-phase ortho-para conversion is governed by intramolecular mixing of the nuclear spin states. The role of ``direct'' ortho-para transitions is shown to be small. Various aspects of the conversion were investigated in detail: pressure and collision partner dependence, isotope effect, temperature dependence. The most decisive information on the spin conversion mechanism is derived from the observation of level-crossing resonances in an electric field and the Quantum Zeno effect induced by collisions.
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"abstract": "Except for ortho- and para-H2, very little is known about nuclear spin\nisomers (or spin modifications) of molecules. The main reason is the lack of\npractical enrichment techniques. Recently a few enrichment methods were\ndeveloped, which opened up new possibilities in the field. These methods are\nbriefly reviewed. Substantial progress in the field has been made by the\nintroduction of Light-Induced Drift as a gas-phase separation tool. This is\nillustrated by extensive data on CH3F, which reveal that the gas-phase\northo-para conversion is governed by intramolecular mixing of the nuclear spin\nstates. The role of ``direct\u0027\u0027 ortho-para transitions is shown to be small.\nVarious aspects of the conversion were investigated in detail: pressure and\ncollision partner dependence, isotope effect, temperature dependence. The most\ndecisive information on the spin conversion mechanism is derived from the\nobservation of level-crossing resonances in an electric field and the Quantum\nZeno effect induced by collisions.",
"arxiv_id": "physics/0204036",
"authors": [
"P. L. Chapovsky",
"L. J. F. Hermans"
],
"categories": [
"physics.chem-ph",
"quant-ph"
],
"journal_ref": "Preprint. Published in Annu. Rev. Phys. Chem. v.50, 315-345 (1999)",
"title": "Nuclear spin conversion in polyatomic molecules",
"url": "https://arxiv.org/abs/physics/0204036"
},
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