{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,5]],"date-time":"2026-04-05T11:16:10Z","timestamp":1775387770260,"version":"3.50.1"},"reference-count":75,"publisher":"AIP Publishing","issue":"6","content-domain":{"domain":["pubs.aip.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2008,8,14]]},"abstract":"<jats:p>Bimolecular collisions between perdeuterated 2,2,6,6-tetramethyl-4-oxopiperidine-l-oxyl molecules in three alkanes have been studied by measuring the electron paramagnetic resonance (EPR) spectral changes induced by spin exchange. We define an \u201cencounter\u201d to be a first-time collision followed by a series of re-encounters prior to the diffusing pair\u2019s escaping each other\u2019s presence. The present work stems from a recent proposal [B. L. Bales et al., J. Phys. Chem. A\u2008107, 9086 (2003)] that an unexpected linear dependence of the spin-exchange-induced EPR line shifts on spin-exchange frequency can be explained by re-encounters of the same probe pair during one encounter. By employing nonlinear least-squares fitting, full use of the information available from the spectral changes allows us to study encounters and re-encounters separately. The encounter rate constants appear to be dominated by hydrodynamic forces, forming a common curve for hexane, decane, and hexadecane when plotted against T\u2215\u03b7, where \u03b7 is the shear viscosity. Unexpectedly, encounters are not dependent on the ratio \u03bc=a\u2215as, where a and as are the van der Waals radii of the nitroxide probe and the solvent, respectively. It is argued that the near coincidence of the resulting encounter rate constant with the hydrodynamic prediction is likely due to a near cancellation of terms in the general diffusion coefficient. Thus, the semblance of hydrodynamic behavior is coincidental rather than intrinsic. In contrast, the mean times between re-encounters do depend on the relative sizes of probe and solvent. For hexane at lower temperatures, the Stokes\u2013Einstein equation apparently describes re-encounters well; however, at higher temperatures and for decane and hexadecane, departures from the hydrodynamic prediction become larger as \u03bc becomes smaller. This is in qualitative agreement with the theory of microscopic diffusion of Hynes et al. [J. Chem. Phys.\u200870, 1456 (1979)]. These departures are well correlated with the free volume available in the solvent; thus, the mean times between re-encounters form a common curve when plotted versus the free volume. Because free volume is manifested macroscopically by the isothermal compressibility, it is expected and observed that the re-encounter rate also forms a common curve across all three solvents when plotted with respect to compressibility. The existence of a common curve for alkanes raises the prospect of using EPR to determine the compressibility of substances such as fossil fuels and biological membranes.<\/jats:p>","DOI":"10.1063\/1.2958922","type":"journal-article","created":{"date-parts":[[2008,8,9]],"date-time":"2008-08-09T22:40:21Z","timestamp":1218321621000},"update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":32,"title":["Nitroxide spin exchange due to re-encounter collisions in a series of n-alkanes"],"prefix":"10.1063","volume":"129","author":[{"given":"Mark R.","family":"Kurban","sequence":"first","affiliation":[{"name":"California State University at Northridge Department of Physics and Astronomy and The Center for Supramolecular Studies, , Northridge, California 91330, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Miroslav","family":"Peric","sequence":"additional","affiliation":[{"name":"California State University at Northridge Department of Physics and Astronomy and The Center for Supramolecular Studies, , Northridge, California 91330, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Barney L.","family":"Bales","sequence":"additional","affiliation":[{"name":"California State University at Northridge Department of Physics and Astronomy and The Center for Supramolecular Studies, , Northridge, California 91330, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"317","published-online":{"date-parts":[[2008,8,8]]},"reference":[{"key":"2023080309572530400_c1","doi-asserted-by":"publisher","first-page":"1094","DOI":"10.1063\/1.1731340","volume":"33","year":"1960","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c2","doi-asserted-by":"publisher","first-page":"3452","DOI":"10.1063\/1.1728131","volume":"45","year":"1966","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c3","doi-asserted-by":"publisher","first-page":"2892","DOI":"10.1063\/1.1733617","volume":"38","year":"1963","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c4","volume-title":"Spin Exchange. Principles and Applications in Chemistry and Biology","year":"1980"},{"key":"2023080309572530400_c5","doi-asserted-by":"publisher","first-page":"189","DOI":"10.1016\/0022-2364(71)90005-9","volume":"5","year":"1971","journal-title":"J. Magn. Reson. (1969-1992)"},{"key":"2023080309572530400_c6","doi-asserted-by":"publisher","first-page":"1995","DOI":"10.1103\/PhysRev.126.1995","volume":"126","year":"1962","journal-title":"Phys. Rev."},{"key":"2023080309572530400_c7","doi-asserted-by":"publisher","first-page":"571","DOI":"10.1051\/jphys:01975003606057100","volume":"36","year":"1975","journal-title":"J. Phys. (Paris)"},{"key":"2023080309572530400_c8","doi-asserted-by":"publisher","first-page":"25","DOI":"10.1080\/00268976700100031","volume":"12","year":"1967","journal-title":"Mol. Phys."},{"key":"2023080309572530400_c9","doi-asserted-by":"publisher","first-page":"3502","DOI":"10.1063\/1.440504","volume":"73","year":"1980","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c10","doi-asserted-by":"publisher","first-page":"1406","DOI":"10.1021\/j100474a012","volume":"83","year":"1979","journal-title":"J. Phys. Chem."},{"key":"2023080309572530400_c11","doi-asserted-by":"publisher","first-page":"225","DOI":"10.1016\/0022-2364(72)90181-3","volume":"7","year":"1972","journal-title":"J. Magn. Reson. (1969-1992)"},{"key":"2023080309572530400_c12","doi-asserted-by":"publisher","first-page":"38","DOI":"10.1021\/j100860a006","volume":"71","year":"1969","journal-title":"J. Phys. Chem."},{"key":"2023080309572530400_c13","doi-asserted-by":"publisher","first-page":"2511","DOI":"10.1063\/1.1673335","volume":"52","year":"1970","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c14","doi-asserted-by":"publisher","first-page":"257","DOI":"10.1016\/0022-2364(87)90288-5","volume":"72","year":"1987","journal-title":"J. Magn. Reson. (1969-1992)"},{"key":"2023080309572530400_c15","doi-asserted-by":"publisher","first-page":"385","DOI":"10.1016\/0022-2364(87)90305-2","volume":"71","year":"1987","journal-title":"J. Magn. Reson. (1969-1992)"},{"key":"2023080309572530400_c16","doi-asserted-by":"publisher","first-page":"133","DOI":"10.1016\/0021-9797(85)90243-7","volume":"108","year":"1985","journal-title":"J. Colloid Interface Sci."},{"key":"2023080309572530400_c17","doi-asserted-by":"publisher","first-page":"4022","DOI":"10.1063\/1.1726566","volume":"44","year":"1966","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c18","doi-asserted-by":"publisher","first-page":"6887","DOI":"10.1063\/1.457358","volume":"91","year":"1989","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c19","doi-asserted-by":"crossref","first-page":"3312","DOI":"10.1063\/1.3192716","volume":"47","year":"1967","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c20","doi-asserted-by":"publisher","first-page":"8707","DOI":"10.1021\/jp970995g","volume":"101","year":"1997","journal-title":"J. Phys. Chem. B"},{"key":"2023080309572530400_c21","doi-asserted-by":"publisher","first-page":"4846","DOI":"10.1021\/jp014518g","volume":"106","year":"2002","journal-title":"J. Phys. Chem. A"},{"key":"2023080309572530400_c22","doi-asserted-by":"publisher","first-page":"9086","DOI":"10.1021\/jp030726s","volume":"107","year":"2003","journal-title":"J. Phys. Chem. A"},{"key":"2023080309572530400_c23","volume-title":"Physical Chemistry","year":"1995","edition":"4th ed."},{"key":"2023080309572530400_c24","doi-asserted-by":"publisher","first-page":"1349","DOI":"10.1063\/1.1740394","volume":"22","year":"1954","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c25","doi-asserted-by":"publisher","first-page":"425","DOI":"10.1016\/0095-8522(49)90023-9","volume":"4","year":"1949","journal-title":"J. Colloid Sci."},{"key":"2023080309572530400_c26","doi-asserted-by":"publisher","first-page":"4926","DOI":"10.1021\/j100222a019","volume":"86","year":"1982","journal-title":"J. Phys. Chem."},{"key":"2023080309572530400_c27","doi-asserted-by":"publisher","first-page":"1232","DOI":"10.1021\/jp003002e","volume":"105","year":"2001","journal-title":"J. Phys. Chem. A"},{"key":"2023080309572530400_c28","doi-asserted-by":"publisher","first-page":"210","DOI":"10.1006\/jmre.1999.1738","volume":"138","year":"1999","journal-title":"J. Magn. Reson."},{"key":"2023080309572530400_c29","doi-asserted-by":"publisher","first-page":"199","DOI":"10.1006\/jmre.1999.1737","volume":"138","year":"1999","journal-title":"J. Magn. Reson."},{"key":"2023080309572530400_c30","first-page":"77","volume-title":"Biological Magnetic Resonance","author":"Berliner","year":"1989"},{"key":"2023080309572530400_c31","doi-asserted-by":"publisher","first-page":"271","DOI":"10.1016\/0022-2364(85)90316-6","volume":"63","year":"1985","journal-title":"J. Magn. Reson. (1969-1992)"},{"key":"2023080309572530400_c32","unstructured":"See EPAPS Document No. E-JCPSA6-129-619830 for an explanation of the derivation. For more information on EPAPS, see http:\/\/www.aip.org\/pubservs\/epaps.html."},{"key":"2023080309572530400_c33","doi-asserted-by":"publisher","first-page":"7368","DOI":"10.1021\/jo034808o","volume":"68","year":"2003","journal-title":"J. Org. Chem."},{"key":"2023080309572530400_c34","doi-asserted-by":"publisher","first-page":"441","DOI":"10.1021\/j100785a001","volume":"68","year":"1964","journal-title":"J. Phys. Chem."},{"key":"2023080309572530400_c35","doi-asserted-by":"publisher","first-page":"527","DOI":"10.1080\/00268978100101501","volume":"43","year":"1981","journal-title":"Mol. Phys."},{"key":"2023080309572530400_c36","volume-title":"Kinetic Theory of Liquids","year":"1955"},{"key":"2023080309572530400_c37","doi-asserted-by":"publisher","first-page":"1471","DOI":"10.1063\/1.1699894","volume":"22","year":"1951","journal-title":"J. Appl. Phys."},{"key":"2023080309572530400_c38","doi-asserted-by":"publisher","first-page":"1164","DOI":"10.1063\/1.1730566","volume":"31","year":"1959","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c39","doi-asserted-by":"publisher","first-page":"8823","DOI":"10.1021\/jp001145v","volume":"104","year":"2000","journal-title":"J. Phys. Chem. A"},{"key":"2023080309572530400_c40","first-page":"399","volume-title":"Biological Magnetic Resonance","author":"Berliner","year":"1989"},{"key":"2023080309572530400_c41","doi-asserted-by":"publisher","first-page":"5857","DOI":"10.1063\/1.440902","volume":"74","year":"1981","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c42","volume-title":"Data Book on the Viscosity of Liquids","year":"1989"},{"key":"2023080309572530400_c43","doi-asserted-by":"publisher","first-page":"2177","DOI":"10.1021\/jp7107494","volume":"112","year":"2008","journal-title":"J. Phys. Chem. A"},{"key":"2023080309572530400_c44","doi-asserted-by":"publisher","first-page":"301","DOI":"10.1146\/annurev.pc.28.100177.001505","volume":"28","year":"1977","journal-title":"Annu. Rev. Phys. Chem."},{"key":"2023080309572530400_c45","doi-asserted-by":"publisher","first-page":"1456","DOI":"10.1063\/1.437584","volume":"70","year":"1979","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c46","doi-asserted-by":"publisher","first-page":"28","DOI":"10.1039\/tf9595500028","volume":"55","year":"1959","journal-title":"Trans. Faraday Soc."},{"key":"2023080309572530400_c47","first-page":"218","volume":"45","year":"1949","journal-title":"Chem. Eng. Prog."},{"key":"2023080309572530400_c48","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1021\/ed047p261","volume":"47","year":"1970","journal-title":"J. Chem. Educ."},{"key":"2023080309572530400_c49","doi-asserted-by":"publisher","first-page":"1971","DOI":"10.1039\/f19726801971","volume":"68","year":"1972","journal-title":"J. Chem. Soc., Faraday Trans. 1"},{"key":"2023080309572530400_c50","doi-asserted-by":"publisher","first-page":"3813","DOI":"10.1063\/1.1673845","volume":"53","year":"1970","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c51","doi-asserted-by":"publisher","first-page":"3764","DOI":"10.1063\/1.431868","volume":"63","year":"1975","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c52","doi-asserted-by":"publisher","first-page":"1475","DOI":"10.1080\/00268977300102631","volume":"26","year":"1973","journal-title":"Mol. Phys."},{"key":"2023080309572530400_c53","doi-asserted-by":"publisher","first-page":"2169","DOI":"10.1021\/j150615a007","volume":"85","year":"1981","journal-title":"J. Phys. Chem."},{"key":"2023080309572530400_c54","doi-asserted-by":"publisher","first-page":"3756","DOI":"10.1021\/j150625a009","volume":"85","year":"1981","journal-title":"J. Phys. Chem."},{"key":"2023080309572530400_c55","doi-asserted-by":"publisher","first-page":"3213","DOI":"10.1063\/1.464094","volume":"98","year":"1993","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c56","doi-asserted-by":"publisher","first-page":"4790","DOI":"10.1021\/jp022470g","volume":"107","year":"2003","journal-title":"J. Phys. Chem. A"},{"key":"2023080309572530400_c57","doi-asserted-by":"publisher","first-page":"3256","DOI":"10.1063\/1.435242","volume":"67","year":"1977","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c58","doi-asserted-by":"publisher","first-page":"3360","DOI":"10.1063\/1.448939","volume":"82","year":"1985","journal-title":"J. Chem. Phys."},{"key":"2023080309572530400_c59","doi-asserted-by":"crossref","first-page":"1590","DOI":"10.1002\/bbpc.19940981214","volume":"98","year":"1994","journal-title":"Ber. Bunsenges. Phys. Chem."},{"key":"2023080309572530400_c60","doi-asserted-by":"publisher","first-page":"127","DOI":"10.1016\/0040-6031(91)80418-I","volume":"181","year":"1991","journal-title":"Thermochim. Acta"},{"key":"2023080309572530400_c61","doi-asserted-by":"publisher","first-page":"49","DOI":"10.1080\/00319109108030632","volume":"23","year":"1991","journal-title":"Phys. Chem. Liq."},{"key":"2023080309572530400_c62","first-page":"345","volume":"127","year":"1990","journal-title":"Acta Chim. Hung."},{"key":"2023080309572530400_c63","doi-asserted-by":"publisher","first-page":"140","DOI":"10.1021\/je60085a007","volume":"25","year":"1980","journal-title":"J. Chem. Eng. Data"},{"key":"2023080309572530400_c64","doi-asserted-by":"publisher","first-page":"67","DOI":"10.1016\/0021-9614(79)90084-3","volume":"11","year":"1979","journal-title":"J. Chem. Thermodyn."},{"key":"2023080309572530400_c65","doi-asserted-by":"publisher","first-page":"787","DOI":"10.1016\/0021-9614(75)90255-4","volume":"7","year":"1975","journal-title":"J. Chem. Thermodyn."},{"key":"2023080309572530400_c66","first-page":"764","volume":"50","year":"1976","journal-title":"Zh. Fiz. Khim."},{"key":"2023080309572530400_c67","doi-asserted-by":"publisher","first-page":"19","DOI":"10.1016\/0021-9614(78)90144-1","volume":"10","year":"1978","journal-title":"J. Chem. Thermodyn."},{"key":"2023080309572530400_c68","doi-asserted-by":"publisher","first-page":"179","DOI":"10.1016\/0021-9614(76)90091-4","volume":"8","year":"1976","journal-title":"J. Chem. Thermodyn."},{"key":"2023080309572530400_c69","doi-asserted-by":"publisher","first-page":"319","DOI":"10.1021\/je9502556","volume":"41","year":"1996","journal-title":"J. Chem. Eng. Data"},{"key":"2023080309572530400_c70","doi-asserted-by":"publisher","first-page":"233","DOI":"10.1021\/je970223d","volume":"43","year":"1998","journal-title":"J. Chem. Eng. Data"},{"key":"2023080309572530400_c71","doi-asserted-by":"publisher","first-page":"923","DOI":"10.1021\/je0342320","volume":"49","year":"2004","journal-title":"J. Chem. Eng. Data"},{"key":"2023080309572530400_c72","doi-asserted-by":"publisher","first-page":"194","DOI":"10.1021\/je60069a018","volume":"21","year":"1976","journal-title":"J. Chem. Eng. Data"},{"key":"2023080309572530400_c73","doi-asserted-by":"publisher","first-page":"196","DOI":"10.1021\/je60069a019","volume":"21","year":"1976","journal-title":"J. Chem. Eng. Data"},{"key":"2023080309572530400_c74","doi-asserted-by":"publisher","first-page":"1095","DOI":"10.1021\/je050060q","volume":"50","year":"2005","journal-title":"J. Chem. Eng. Data"},{"key":"2023080309572530400_c75","year":"2003"}],"container-title":["The Journal of Chemical Physics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.aip.org\/aip\/jcp\/article-pdf\/doi\/10.1063\/1.2958922\/13914319\/064501_1_online.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.aip.org\/aip\/jcp\/article-pdf\/doi\/10.1063\/1.2958922\/13914319\/064501_1_online.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,8,3]],"date-time":"2023-08-03T09:57:43Z","timestamp":1691056663000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.aip.org\/jcp\/article\/129\/6\/064501\/953419\/Nitroxide-spin-exchange-due-to-re-encounter"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2008,8,8]]},"references-count":75,"journal-issue":{"issue":"6","published-print":{"date-parts":[[2008,8,14]]}},"URL":"https:\/\/doi.org\/10.1063\/1.2958922","relation":{},"ISSN":["0021-9606","1089-7690"],"issn-type":[{"value":"0021-9606","type":"print"},{"value":"1089-7690","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2008,8,14]]},"published":{"date-parts":[[2008,8,8]]},"article-number":"064501"}}