[ { "id": "authors:16ggw-cw493", "collection": "authors", "collection_id": "16ggw-cw493", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20161118-133421969", "type": "article", "title": "SN Refsdal: Classification as a Luminous and Blue SN 1987A-like Type II Supernova", "author": [ { "family_name": "Kelly", "given_name": "P. L.", "orcid": "0000-0003-3142-997X", "clpid": "Kelly-P-L" }, { "family_name": "Brammer", "given_name": "G.", "clpid": "Brammer-G" }, { "family_name": "Selsing", "given_name": "J.", "clpid": "Selsing-J" }, { "family_name": "Foley", "given_name": "R. J.", "clpid": "Foley-R-J" }, { "family_name": "Hjorth", "given_name": "J.", "orcid": "0000-0002-4571-2306", "clpid": "Hjorth-J" }, { "family_name": "Rodney", "given_name": "S. A.", "orcid": "0000-0003-1947-687X", "clpid": "Rodney-S-A" }, { "family_name": "Christensen", "given_name": "L.", "clpid": "Christensen-L-E" }, { "family_name": "Strolger", "given_name": "L.-G.", "clpid": "Strolger-L-G" }, { "family_name": "Filippenko", "given_name": "A. V.", "orcid": "0000-0003-3460-0103", "clpid": "Filippenko-A-V" }, { "family_name": "Treu", "given_name": "T.", "orcid": "0000-0002-8460-0390", "clpid": "Treu-Tommaso" }, { "family_name": "Steidel", "given_name": "C. C.", "orcid": "0000-0002-4834-7260", "clpid": "Steidel-C-C" }, { "family_name": "Strom", "given_name": "A.", "orcid": "0000-0001-6369-1636", "clpid": "Strom-A-L" }, { "family_name": "Riess", "given_name": "A. G.", "clpid": "Riess-A-G" }, { "family_name": "Zitrin", "given_name": "A.", "orcid": "0000-0002-0350-4488", "clpid": "Zitrin-Adi" }, { "family_name": "Schmidt", "given_name": "K. B.", "clpid": "Schmidt-K-B" }, { "family_name": "Brada\u010d", "given_name": "M.", "clpid": "Brada\u010d-M" }, { "family_name": "Jha", "given_name": "S. W.", "orcid": "0000-0001-8738-6011", "clpid": "Jha-S-W" }, { "family_name": "Graham", "given_name": "M. L.", "orcid": "0000-0002-9154-3136", "clpid": "Graham-M-L" }, { "family_name": "McCully", "given_name": "C.", "orcid": "0000-0001-5807-7893", "clpid": "McCully-C" }, { "family_name": "Graur", "given_name": "O.", "clpid": "Graur-O" }, { "family_name": "Weiner", "given_name": "B. J.", "clpid": "Weiner-B-J" }, { "family_name": "Silverman", "given_name": "J. M.", "orcid": "0000-0003-3325-3365", "clpid": "Silverman-J-M" }, { "family_name": "Taddia", "given_name": "F.", "orcid": "0000-0002-2387-6801", "clpid": "Taddia-F" } ], "abstract": "We have acquired Hubble Space Telescope (HST) and Very Large Telescope near-infrared spectra and images of supernova (SN) Refsdal after its discovery as an Einstein cross in fall 2014. The HST light curve of SN Refsdal has a shape consistent with the distinctive, slowly rising light curves of SN 1987A-like SNe, and we find strong evidence for a broad H\u03b1 P-Cygni profile and Na I D absorption in the HST grism spectrum at the redshift (z = 1.49) of the spiral host galaxy. SNe IIn, largely powered by circumstellar interaction, could provide a good match to the light curve of SN Refsdal, but the spectrum of a SN IIn would not show broad and strong H\u03b1 and Na I D absorption. From the grism spectrum, we measure an H\u03b1 expansion velocity consistent with those of SN 1987A-like SNe at a similar phase. The luminosity, evolution, and Gaussian profile of the H\u03b1 emission of the WFC3 and X-shooter spectra, separated by ~2.5 months in the rest frame, provide additional evidence that supports the SN 1987A-like classification. In comparison with other examples of SN 1987A-like SNe, photometry of SN Refsdal favors bluer B \u2212 V and V \u2212 R colors and one of the largest luminosities for the assumed range of potential magnifications. The evolution of the light curve at late times will provide additional evidence about the potential existence of any substantial circumstellar material. Using MOSFIRE and X-shooter spectra, we estimate a subsolar host-galaxy metallicity (8.3 \u00b1 0.1 dex and <8.4 dex, respectively) near the explosion site.", "doi": "10.3847/0004-637X/831/2/205", "issn": "0004-637X", "publisher": "American Astronomical Society", "publication": "Astrophysical Journal", "publication_date": "2016-11-10", "series_number": "2", "volume": "831", "issue": "2", "pages": "Art. No. 205" }, { "id": "authors:nxm20-6as71", "collection": "authors", "collection_id": "nxm20-6as71", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141210-083740627", "type": "article", "title": "The imprint of atmospheric evolution in the D/H of Hesperian clay minerals on Mars", "author": [ { "family_name": "Mahaffy", "given_name": "P. R.", "orcid": "0000-0003-1896-1726", "clpid": "Mahaffy-P-R" }, { "family_name": "Webster", "given_name": "C. R.", "clpid": "Webster-C-R" }, { "family_name": "Stern", "given_name": "J. C.", "orcid": "0000-0002-0162-8807", "clpid": "Stern-J-C" }, { "family_name": "Brunner", "given_name": "A. E.", "clpid": "Brunner-A-E" }, { "family_name": "Atreya", "given_name": "S. K.", "orcid": "0000-0002-1972-1815", "clpid": "Atreya-S-K" }, { "family_name": "Conrad", "given_name": "P. G.", "clpid": "Conrad-P-G" }, { "family_name": "Domagal-Goldman", "given_name": "S.", "clpid": "Domagal-Goldman-S" }, { "family_name": "Eigenbrode", "given_name": "J. L.", "orcid": "0000-0003-3089-1986", "clpid": "Eigenbrode-J-L" }, { "family_name": "Flesch", "given_name": "G. J.", "clpid": "Flesch-G-J" }, { "family_name": "Christensen", "given_name": "L. E.", "clpid": "Christensen-L-E" }, { "family_name": "Franz", "given_name": "H. B.", "clpid": "Franz-H-B" }, { "family_name": "Freissinet", "given_name": "C.", "clpid": "Freissinet-C" }, { "family_name": "Glavin", "given_name": "D. P.", "orcid": "0000-0001-7779-7765", "clpid": "Glavin-D-P" }, { "family_name": "Grotzinger", "given_name": "J. P.", "orcid": "0000-0001-9324-1257", "clpid": "Grotzinger-J-P" }, { "family_name": "Jones", "given_name": "J. H.", "clpid": "Jones-J-H" }, { "family_name": "Leshin", "given_name": "L. A.", "clpid": "Leshin-L-A" }, { "family_name": "Malespin", "given_name": "C.", "orcid": "0000-0002-5852-5016", "clpid": "Malespin-C-A" }, { "family_name": "McAdam", "given_name": "A. C.", "clpid": "McAdam-A-C" }, { "family_name": "Ming", "given_name": "D. W.", "orcid": "0000-0003-0567-8876", "clpid": "Ming-Douglas-W" }, { "family_name": "Navarro-Gonz\u00e1lez", "given_name": "R.", "clpid": "Navarro-Gonz\u00e1lez-Rafael" }, { "family_name": "Niles", "given_name": "P. B.", "clpid": "Niles-P-B" }, { "family_name": "Owen", "given_name": "T.", "clpid": "Owen-T-C" }, { "family_name": "Pavlov", "given_name": "A. A.", "clpid": "Pavlov-A-A" }, { "family_name": "Steele", "given_name": "A.", "clpid": "Steele-A-D" }, { "family_name": "Trainer", "given_name": "M. G.", "clpid": "Trainer-M-G" }, { "family_name": "Williford", "given_name": "K. H.", "orcid": "0000-0003-0633-408X", "clpid": "Williford-K-H" }, { "family_name": "Wray", "given_name": "J. J.", "clpid": "Wray-J-J" }, { "literal": "MSL Science Team" } ], "abstract": "The deuterium to hydrogen (D/H) ratio in strongly bound water or hydroxyl groups in ancient martian clays retains the imprint of the water of formation of these minerals. Curiosity's Sample Analysis at Mars (SAM) experiment measured thermally evolved water and hydrogen gas released between 550\u00b0C and 950\u00b0C from samples of Hesperian era Gale crater smectite to determine this isotope ratio. The D/H value is 3.0 (\u00b10.2) times the ratio in Standard Mean Ocean Water (SMOW). The D/H ratio in this ~3 billion year old mudstone that is half that of the present martian atmosphere but substantially higher than that expected in very early Mars indicates an extended history of hydrogen escape and desiccation of the planet.", "doi": "10.1126/science.1260291", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2015-01-23", "series_number": "6220", "volume": "347", "issue": "6220", "pages": "412-414" }, { "id": "authors:95yta-2sj90", "collection": "authors", "collection_id": "95yta-2sj90", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141210-083300697", "type": "article", "title": "Mars methane detection and variability at Gale crater", "author": [ { "family_name": "Webster", "given_name": "Christopher R.", "clpid": "Webster-C-R" }, { "family_name": "Mahaffy", "given_name": "Paul R.", "orcid": "0000-0003-1896-1726", "clpid": "Mahaffy-P-R" }, { "family_name": "Atreya", "given_name": "Sushil K.", "orcid": "0000-0002-1972-1815", "clpid": "Atreya-S-K" }, { "family_name": "Flesch", "given_name": "Gregory J.", "clpid": "Flesch-G-J" }, { "family_name": "Mischna", "given_name": "Michael A.", "orcid": "0000-0002-8022-5319", "clpid": "Mischna-M-A" }, { "family_name": "Meslin", "given_name": "Pierre-Yves", "orcid": "0000-0002-0703-3951", "clpid": "Meslin-P-Y" }, { "family_name": "Farley", "given_name": "Kenneth A.", "orcid": "0000-0002-7846-7546", "clpid": "Farley-K-A" }, { "family_name": "Conrad", "given_name": "Pamela G.", "clpid": "Conrad-P-G" }, { "family_name": "Christensen", "given_name": "Lance E.", "clpid": "Christensen-L-E" }, { "family_name": "Pavlov", "given_name": "Alexander A.", "clpid": "Pavlov-A-A" }, { "family_name": "Mart\u00edn-Torres", "given_name": "Javier", "clpid": "Mart\u00edn-Torres-J" }, { "family_name": "Zorzano", "given_name": "Mar\u00eda-Paz", "clpid": "Zorzano-M-P" }, { "family_name": "McConnochie", "given_name": "Timothy H.", "clpid": "McConnochie-T-H" }, { "family_name": "Owen", "given_name": "Tobias", "clpid": "Owen-T" }, { "family_name": "Eigenbrode", "given_name": "Jennifer L.", "orcid": "0000-0003-3089-1986", "clpid": "Eigenbrode-J-L" }, { "family_name": "Glavin", "given_name": "Daniel P.", "orcid": "0000-0001-7779-7765", "clpid": "Glavin-D-P" }, { "family_name": "Steele", "given_name": "Andrew", "clpid": "Steele-A-D" }, { "family_name": "Malespin", "given_name": "Charles A.", "orcid": "0000-0002-5852-5016", "clpid": "Malespin-C-A" }, { "family_name": "Archer", "given_name": "P. Douglas Jr.", "clpid": "Archer-P-D-Jr" }, { "family_name": "Sutter", "given_name": "Brad", "orcid": "0000-0002-3036-170X", "clpid": "Sutter-B" }, { "family_name": "Coll", "given_name": "Patrice", "clpid": "Coll-P" }, { "family_name": "Freissinet", "given_name": "Caroline", "clpid": "Freissinet-C" }, { "family_name": "McKay", "given_name": "Christopher P.", "clpid": "McKay-C-P" }, { "family_name": "Moores", "given_name": "John E.", "clpid": "Moores-J-E" }, { "family_name": "Schwenzer", "given_name": "Susanne P.", "orcid": "0000-0002-9608-0759", "clpid": "Schwenzer-S-P" }, { "family_name": "Bridges", "given_name": "John C.", "orcid": "0000-0002-9579-5779", "clpid": "Bridges-J-C" }, { "family_name": "Navarro-Gonz\u00e1lez", "given_name": "Rafael", "clpid": "Navarro-Gonz\u00e1lez-Rafael" }, { "family_name": "Gellert", "given_name": "Ralf", "orcid": "0000-0001-7928-834X", "clpid": "Gellert-R" }, { "family_name": "Lemmon", "given_name": "Mark T.", "clpid": "Lemmon-M-T" }, { "literal": "MSL Science Team" } ], "abstract": "Reports of plumes or patches of methane in the Martian atmosphere that vary over monthly timescales have defied explanation to date. From in situ measurements made over a 20-month period by the Tunable Laser Spectrometer (TLS) of the Sample Analysis at Mars (SAM) instrument suite on Curiosity at Gale Crater, we report detection of background levels of atmospheric methane of mean value 0.69 \u00b1 0.25 ppbv at the 95% confidence interval (CI). This abundance is lower than model estimates of ultraviolet (UV) degradation of accreted interplanetary dust particles (IDP's) or carbonaceous chondrite material. Additionally, in four sequential measurements spanning a 60-sol period, we observed elevated levels of methane of 7.2 \u00b1 2.1 (95% CI) ppbv implying that Mars is episodically producing methane from an additional unknown source.", "doi": "10.1126/science.1261713", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2015-01-23", "series_number": "6220", "volume": "347", "issue": "6220", "pages": "415-417" }, { "id": "authors:j0r83-fcv04", "collection": "authors", "collection_id": "j0r83-fcv04", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20200505-091430499", "type": "article", "title": "Isotope Ratios of H, C, and O in CO\u2082 and H\u2082O of the Martian Atmosphere", "author": [ { "family_name": "Webster", "given_name": "Chris R.", "clpid": "Webster-C-R" }, { "family_name": "Mahaffy", "given_name": "Paul R.", "orcid": "0000-0003-1896-1726", "clpid": "Mahaffy-P-R" }, { "family_name": "Flesch", "given_name": "Gregory J.", "clpid": "Flesch-G-J" }, { "family_name": "Niles", "given_name": "Paul B.", "clpid": "Niles-P-B" }, { "family_name": "Jones", "given_name": "John H.", "clpid": "Jones-J-H" }, { "family_name": "Leshin", "given_name": "Laurie A.", "clpid": "Leshin-L-A" }, { "family_name": "Atreya", "given_name": "Sushil K.", "orcid": "0000-0002-1972-1815", "clpid": "Atreya-S-K" }, { "family_name": "Stern", "given_name": "Jennifer C.", "orcid": "0000-0002-0162-8807", "clpid": "Stern-J-C" }, { "family_name": "Christensen", "given_name": "Lance E.", "clpid": "Christensen-L-E" }, { "family_name": "Owen", "given_name": "Tobias", "clpid": "Owen-T" }, { "family_name": "Franz", "given_name": "Heather", "clpid": "Franz-H-B" }, { "family_name": "Pepin", "given_name": "Robert O.", "clpid": "Pepin-R-O" }, { "family_name": "Steele", "given_name": "Andrew", "clpid": "Steele-A-D" }, { "literal": "MSL Science Team" } ], "abstract": "Stable isotope ratios of H, C, and O are powerful indicators of a wide variety of planetary geophysical processes, and for Mars they reveal the record of loss of its atmosphere and subsequent interactions with its surface such as carbonate formation. We report in situ measurements of the isotopic ratios of D/H and \u00b9\u2078O/\u00b9\u2076O in water and \u00b9\u00b3C/\u00b9\u00b2C, \u00b9\u2078O/\u00b9\u2076O, \u00b9\u2077O/\u00b9\u2076O, and \u00b9\u00b3C\u00b9\u2078O/\u00b9\u00b2C\u00b9\u2076O in carbon dioxide, made in the martian atmosphere at Gale Crater from the Curiosity rover using the Sample Analysis at Mars (SAM)'s tunable laser spectrometer (TLS). Comparison between our measurements in the modern atmosphere and those of martian meteorites such as ALH 84001 implies that the martian reservoirs of CO\u2082 and H\u2082O were largely established ~4 billion years ago, but that atmospheric loss or surface interaction may be still ongoing.", "doi": "10.1126/science.1237961", "issn": "0036-8075", "publisher": "American Association for the Advancement of Science", "publication": "Science", "publication_date": "2013-07-19", "series_number": "6143", "volume": "341", "issue": "6143", "pages": "260-263" }, { "id": "authors:tgsw7-vx192", "collection": "authors", "collection_id": "tgsw7-vx192", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170606-131245100", "type": "article", "title": "Experimental and ab Initio Study of the HO_2\u00b7CH_3OH Complex: Thermodynamics and Kinetics of Formation", "author": [ { "family_name": "Christensen", "given_name": "Lance E.", "clpid": "Christensen-L-E" }, { "family_name": "Okumura", "given_name": "Mitchio", "orcid": "0000-0001-6874-1137", "clpid": "Okumura-M" }, { "family_name": "Hansen", "given_name": "Jaron C.", "clpid": "Hansen-J-C" }, { "family_name": "Sander", "given_name": "Stanley P.", "orcid": "0000-0003-1424-3620", "clpid": "Sander-S-P" }, { "family_name": "Francisco", "given_name": "Joseph S.", "clpid": "Francisco-J-S" } ], "abstract": "Near-infrared spectroscopy was used to monitor HO_2 formed by pulsed laser photolysis of Cl_2\u2212O_2\u2212CH_3OH\u2212N_2 mixtures. On the microsecond time scale, [HO_2] exhibited a time dependence consistent with a mechanism in which [HO_2] approached equilibrium via HO_2 + HO_3OH^M\u21c6_M HO_2\u00b7CH_3OH (3, \u22123). The equilibrium constant for reaction 3, Kp, was measured between 231 and 261 K at 50 and 100 Torr, leading to standard reaction enthalpy and entropy values (1 \u03c3) of \u0394_rH\u00b0_(246K) = \u221237.4 \u00b1 4.8 kJ mol^(-1) and \u0394_rS\u00b0_(246K) = \u2212100 \u00b1 19 J mol^(-1) K^(-1). The effective bimolecular rate constant, k_3, for formation of the HO_2\u00b7CH_3OH complex is 2.8^(+7.5)_(-2.0)\u00b710^(-15)\u00b7exp[(1800 \u00b1 500)/T] cm^3 molecule^(-1) s^(-1) at 100 Torr (1 \u03c3). Ab initio calculations of the optimized structure and energetics of the HO_2\u00b7CH_3OH complex were performed at the CCSD(T)/6-311++G(3df,3pd)//MP2(full)/6-311++G(2df,2pd) level. The complex was found to have a strong hydrogen bond (D_e = 43.9 kJ mol^(-1)) with the hydrogen in HO_2 binding to the oxygen in CH_3OH. The calculated enthalpy for association is \u0394_rH\u00b0_(245K) = \u221236.8 kJ mol^(-1). The potentials for the torsion about the O_2\u2212H bond and for the hydrogen-bond stretch were computed and 1D vibrational levels determined. After explicitly accounting for these degrees of freedom, the calculated Third Law entropy of association is \u0394_rS\u00b0_(245K) = \u2212106 J mol^(-1) K^(-1). Both the calculated enthalpy and entropy of association are in reasonably good agreement with experiment. When combined with results from our previous study (Christensen et al. Geophys. Res. Lett. 2002, 29; doi:10.1029/2001GL014525), the rate coefficient for the reaction of HO_2 with the complex, HO_2 + HO_2\u00b7CH_3-OH, is determined to be (2.1 \u00b1 0.7) \u00d7 10^(-11) cm^3 molecule^(-1) s^(-1). The results of the present work argue for a reinterpretation of the recent measurement of the HO_2 self-reaction rate constant by Stone and Rowley (Phys. Chem. Chem. Phys. 2005, 7, 2156). Significant complex concentrations are present at the high methanol concentrations used in that work and lead to a nonlinear methanol dependence of the apparent rate constant. This nonlinearity introduces substantial uncertainty in the extrapolation to zero methanol.", "doi": "10.1021/jp056579a", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2006-06-06", "series_number": "21", "volume": "110", "issue": "21", "pages": "6948-6959" }, { "id": "authors:17rz8-pp861", "collection": "authors", "collection_id": "17rz8-pp861", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20170524-082812028", "type": "article", "title": "Measurements of the Rate Constant of HO_2 + NO_2 + N_2 \u2192 HO_2NO_2 + N_2 Using Near-Infrared Wavelength-Modulation Spectroscopy and UV\u2212Visible Absorption Spectroscopy", "author": [ { "family_name": "Christensen", "given_name": "Lance E.", "clpid": "Christensen-L-E" }, { "family_name": "Okumura", "given_name": "Mitchio", "orcid": "0000-0001-6874-1137", "clpid": "Okumura-M" }, { "family_name": "Sander", "given_name": "Stanley P.", "orcid": "0000-0003-1424-3620", "clpid": "Sander-S-P" }, { "family_name": "Friedl", "given_name": "Randall R.", "clpid": "Friedl-R-R" }, { "family_name": "Miller", "given_name": "Charles E.", "orcid": "0000-0002-9380-4838", "clpid": "Miller-C-E" }, { "family_name": "Sloan", "given_name": "James J.", "clpid": "Sloan-J-J" } ], "abstract": "Rate coefficients for the reaction HO_2 + NO_2 + N_2 \u2192 HO_2NO_2 + N_2 (reaction 1) were measured using simultaneous near-IR and UV spectroscopy from 220 to 298 K and from 45 to 200 Torr. Using the data acquired in the present experiment, the low-pressure and high-pressure limit rate constants for reaction 1 were determined to be k_o = (2.1 \u00b1 0.1) \u00d7 10^(-31) \u00d7 (T/300)^(-(3.1\u00b10.3)) cm^6 molecule^(-2) s^(-1) and k\u221e = (2.4 \u00b1 0.1) \u00d7 10^(-12) \u00d7 (T/300))^(-(1.9\u00b10.5)) cm^3 molecule^(-1) s^(-1), using the expressions for rate constants adopted by the NASA data evaluation panel (F_c = 0.6). The reaction rate was significantly enhanced in the presence of methanol due to a chaperone effect involving an HO_2\u00b7CH_3OH complex. Enhancement parameters for this process were quantified as a function of temperature. During the course of our studies, we observed an unexpected time-dependent UV absorption unaccounted for in previous examinations of reaction 1 that employed UV spectroscopy to monitor HO_2. We show that this absorption, which may have led to errors in those prior studies, is due to the process NO_2 + NO_2 \u21c4 N_2O_4 (reaction 3). Using UV\u2212visible spectroscopy, we determine k_(-3) to be (36 \u00b1 10) s^(-1) at 231 K and 100 Torr using the NASA-recommended equilibrium constant for the dimerization of NO_2. This represents the first measurement of k_(-3) at T < 250 K.", "doi": "10.1021/jp035905o", "issn": "1089-5639", "publisher": "American Chemical Society", "publication": "Journal of Physical Chemistry A", "publication_date": "2004-01-08", "series_number": "1", "volume": "108", "issue": "1", "pages": "80-91" }, { "id": "authors:12q5y-14764", "collection": "authors", "collection_id": "12q5y-14764", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141027-085804530", "type": "article", "title": "Kinetics of HO_2 + HO_2 \u2192 H_2O_2 + O_2: Implications for Stratospheric H_2O_2", "author": [ { "family_name": "Christensen", "given_name": "L. E.", "clpid": "Christensen-L-E" }, { "family_name": "Okumura", "given_name": "M.", "orcid": "0000-0001-6874-1137", "clpid": "Okumura-M" }, { "family_name": "Sander", "given_name": "S. P.", "orcid": "0000-0003-1424-3620", "clpid": "Sander-S-P" }, { "family_name": "Salawitch", "given_name": "R. J.", "clpid": "Salawitch-R-J" }, { "family_name": "Toon", "given_name": "G. C.", "orcid": "0000-0003-4174-7541", "clpid": "Toon-G-C" }, { "family_name": "Sen", "given_name": "B.", "clpid": "Sen-B" }, { "family_name": "Blavier", "given_name": "J.-F.", "clpid": "Blavier-J-F-L" }, { "family_name": "Jucks", "given_name": "K. W.", "clpid": "Jucks-K-W" } ], "abstract": "The reaction HO_2 + HO_2 \u2192 H_2O_2 + O_2(1) has been studied at 100 Torr and 222 K to 295 K. Experiments employing photolysis of Cl_2/CH_3OH/O_2/N_2 and F_2/H_2/O_2/N_2 gas mixtures to produce HO_2 confirmed that methanol enhanced the observed reaction rate. At 100 Torr, zero methanol, k_1 = (8.8 \u00b1 0.9) 10^(\u221213) \u00d7 exp[(210 \u00b1 26)/T] cm^3 molecule^(\u22121) s^(\u22121) (2\u03c3 uncertainties), which agrees with current recommendations at 295 K but is nearly 2 times slower at 231 K. The general expression for k_1, which includes the dependence on bath gas density, is k_1 = (1.5 \u00b1 0.2) \u00d7 10^(\u221212) \u00d7 exp[(19 \u00b1 31)/T] + 1.7 \u00d7 10^(\u221233) \u00d7 [M] \u00d7 exp[1000/T], where the second term is taken from the JPL00-3 recommendation. The revised rate largely accounts for a discrepancy between modeled and measured [H_2O_2] in the lower to middle stratosphere.", "doi": "10.1029/2001GL014525", "issn": "0094-8276", "publisher": "American Geophysical Union", "publication": "Geophysical Research Letters", "publication_date": "2002-05", "series_number": "9", "volume": "29", "issue": "9", "pages": "Art. No. 1299" }, { "id": "authors:3wyqz-0py58", "collection": "authors", "collection_id": "3wyqz-0py58", "cite_using_url": "https://resolver.caltech.edu/CaltechAUTHORS:20141216-133615278", "type": "article", "title": "Near-IR linestrength measurements of hydroperoxy radicals", "author": [ { "family_name": "Oh", "given_name": "Daniel B.", "clpid": "Oh-Daniel-B" }, { "family_name": "Stanton", "given_name": "Alan C.", "clpid": "Stanton-A-C" }, { "family_name": "Christensen", "given_name": "Lance", "clpid": "Christensen-L-E" } ], "abstract": "Hydroperoxy (HO_2) radicals play crucial roles in atmospheric chemistry as a reservoir specie of hydroxyl (OH) radicals. In situ, direct monitoring of HO_2 radicals under pertinent atmospheric conditions provide important clues to assessing the importance of different atmospheric reactions that take places and in testing and refining atmospheric reaction models. Concurrent laboratory measurement of HO_2 reaction rates are also important in order to build a database of reaction rates which are needed for the atmospheric reaction modeling. Spectroscopic detection of HO_2 radical in UV is complicated by the broad, featureless absorption due to predissociation.", "issn": "0065-7727", "publisher": "American Chemical Society", "publication": "Abstracts of Papers of the American Chemical Society", "publication_date": "2000-03-26", "volume": "219", "pages": "PHYS-250" } ]