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Iribarren J, Jimenez JJ, Brouard M, Lorente L, Perez R, Lorenzo L, Raja L, Palmero S, Perez N, Martinez R, Mora M. TNFβ +250 polymorphism and hyperdynamic state in cardiac surgery with extracorporeal circulation. Crit Care 2009. [PMCID: PMC4084237 DOI: 10.1186/cc7515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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102
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Lorente L, Palmero S, Iribarren J, Jiménez J, Garcia C, Galván R, Castedo J, Martínez J, Brouard M, Martín M, Mora M. Arterial catheter-related infection according to the catheter site. Crit Care 2009. [PMCID: PMC4084072 DOI: 10.1186/cc7350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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103
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Brouard M, Jimenez JJ, Iribarren J, Lorente L, Perez R, Lorenzo L, Palmero S, Raja L, Perez N, Martinez R, Mora ML. Preoperative left atrial dysfunction and new-onset atrial fibrillation in cardiac surgery patients. Crit Care 2009. [PMCID: PMC4084043 DOI: 10.1186/cc7321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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104
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Jimenez J, Iribarren J, Brouard M, Lorenzo L, Lorente L, Perez R, Perez N, Raja L, Martinez R, Luisa M. Relative adrenal insufficiency in cardiopulmonary bypass surgery patients: impact on the postoperative hemodynamic status. Crit Care 2009. [PMCID: PMC4084214 DOI: 10.1186/cc7492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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105
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Brouard M, Campbell EK, Johnsen AJ, Vallance C, Yuen WH, Nomerotski A. Velocity map imaging in time of flight mass spectrometry. Rev Sci Instrum 2008; 79:123115. [PMID: 19123553 DOI: 10.1063/1.3036978] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A new variation on time of flight mass spectrometry is presented, which uses a fast framing charge coupled device camera to velocity map image multiple product masses in a single acquisition. The technique is demonstrated on two photofragmentation processes, those of CS(2) and CH(3)S(2)CH(3) (dimethyldisulfide) at a photolysis wavelength of 193 nm. In both cases, several mass fragments are imaged simultaneously, and speed distributions and anisotropy parameters are extracted that are comparable to those obtained by imaging each fragment separately in conventional velocity map imaging studies.
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Affiliation(s)
- M Brouard
- The Department of Chemistry, The Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
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106
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Kłos J, Alexander MH, Brouard M, Eyles CJ, Aoiz FJ. A new potential energy surface for OH(A Σ2+)–Ar: The van der Waals complex and scattering dynamics. J Chem Phys 2008; 129:054301. [DOI: 10.1063/1.2957745] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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107
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Brouard M, Antoine P, Labbe J. [Subjective experience and disability work: qualitative analysis among 17 paraplegic patients]. Ann Readapt Med Phys 2008; 51:394-402. [PMID: 18550195 DOI: 10.1016/j.annrmp.2008.04.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Accepted: 04/12/2008] [Indexed: 05/26/2023]
Abstract
This paper presents a phenomenological study illustrative how paraplegia may have a serious debilitating impact on the sufferer's subjective experience. Exploratory interviews were conducted with seventeen patients and the transcripts subjected to qualitative analysis. The interpretative phenomenological analysis points to the powerful ways in which paraplegia has negative impact on patients' experience and well-being. Some of the participants describe two major approaches of their situation: dimensional (the links between disability and society, others and self) and temporal (the "disability work"). The results section gives a detailed account of these processes at work. The results are then considered in relation to relevant constructs in the literature, including grief work, illness work and identity, adaptation and acceptance.
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Affiliation(s)
- M Brouard
- Université Lille-Nord de France, B.P. 60149, 59653 Villeneuve d'Ascq cedex, France
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108
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Ramos LL, Lecuona M, Jiménez A, Iribarren J, Castedo J, Galván R, García C, Jiménez J, Brouard M, Mora M, Sierra A. An endotracheal tube with a polyurethane cuff and subglottic secretion drainage reduces the incidence of primary and secondary endogenous ventilator-associated pneumonia. Crit Care 2008. [PMCID: PMC4088417 DOI: 10.1186/cc6267] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
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109
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Ramos LL, García C, Iribarren J, Castedo J, Galván R, Jiménez J, Brouard M, Santacreu R, Lorenzo L, Martín M, Mora M. Colonization and infection by potential Gram-negative multiresistant microorganism in a medical–surgical ICU. Crit Care 2008. [PMCID: PMC4088407 DOI: 10.1186/cc6257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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110
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Lorenzo L, Brouard M, Iribarren J, Jimenez J, Lorente L, Perez R, Palmero S, Santacreu R, Martinez R, Mora M. Etomidate and relative adrenal insufficiency in cardiopulmonary bypass surgery: impact on the postoperative hemodynamic status. Crit Care 2008. [PMCID: PMC4088643 DOI: 10.1186/cc6493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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111
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Brouard M, Jimenez J, Iribarren J, Lorenzo L, Palmero S, Rodriguez I, Perez R, Machado P, Raya J, Rodriguez J, Garrido P, Nassar I, De la Llana R, Martinez R, Mora M. Postoperative dose of tranexamic acid decreases postoperative bleeding and inflammatory response associated with cardiopulmonary bypass: a randomized, double-blind study. Crit Care 2008. [PMCID: PMC4088593 DOI: 10.1186/cc6443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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112
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Ramos LL, Castedo J, Galván R, García C, Iribarren J, Jiménez J, Brouard M, Lorenzo L, Palmero S, Martín M, Mora M. Incidence of nosocomial infection in patients with nontraumatic or traumatic coma. Crit Care 2008. [PMCID: PMC4088383 DOI: 10.1186/cc6233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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113
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Ramos LL, García C, Iribarren J, Castedo J, Jiménez J, Brouard M, Henry C, Santacreu R, Martín M, Mora M. Catheter-related bloodstream infection according to central venous accesses. Crit Care 2008. [PMCID: PMC4088409 DOI: 10.1186/cc6259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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114
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Jimenez J, Iribarren J, Brouard M, Lorente L, Perez R, Palmero S, Henry C, Malaga J, Lorenzo J, Serrano N, Martinez R, Mora M. Clinical outcome and mortality associated with postoperative low cardiac output after cardiopulmonary bypass: a cohort study. Crit Care 2008. [PMCID: PMC4088612 DOI: 10.1186/cc6462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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115
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Iribarren J, Naranjo C, Mora M, Galvan R, Perez R, Lorenzo L, Brouard M, Barragan A, Laynez I, Jimenez J. Left ventricular TEI index: comparison between flow and tissue Doppler analyses and its association with postoperative atrial fibrillation in cardiopulmonary bypass surgery. Crit Care 2008. [PMCID: PMC4088617 DOI: 10.1186/cc6467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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116
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Brouard M, Iribarren J, Jiménez J, Lorente L, Perez R, Santacreu R, Santana M, Rodriguez J, Machado P, Martinez R, Mora M. Tranexamic acid effects on postoperative bleeding in cardiopulmonary bypass surgery according to the plasminogen activator inhibitor-1 polymorphism. Crit Care 2008. [PMCID: PMC4088835 DOI: 10.1186/cc6685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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117
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Brouard M, Goman A, Horrocks SJ, Johnsen AJ, Quadrini F, Yuen WH. The photodissociation dynamics of ozone at 226 and 248nm: O(PJ3) atomic angular momentum polarization. J Chem Phys 2007; 127:144304. [DOI: 10.1063/1.2790890] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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118
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Brouard M, Green AV, Quadrini F, Vallance C. Photodissociation dynamics of OCS at 248nm: The S(D21) atomic angular momentum polarization. J Chem Phys 2007; 127:084304. [PMID: 17764245 DOI: 10.1063/1.2757618] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dissociation of OCS has been investigated subsequent to excitation at 248 nm. Speed distributions, speed dependent translational anisotropy parameters, angular momentum alignment, and orientation are reported for the channel leading to S((1)D(2)). In agreement with previous experiments, two product speed regimes have been identified, correlating with differing degrees of rotational excitation in the CO coproducts. The velocity dependence of the translational anisotropy is also shown to be in agreement with previous work. However, contrary to previous interpretations, the speed dependence is shown to primarily reflect the effects of nonaxial recoil and to be consistent with predominant excitation to the 2 (1)A(') electronic state. It is proposed that the associated electronic transition moment is polarized in the molecular plane, at an angle greater than approximately 60 degrees to the initial linear OCS axis. The atomic angular momentum polarization data are interpreted in terms of a simple long-range interaction model to help identify likely surfaces populated during dissociation. Although the model neglects coherence between surfaces, the polarization data are shown to be consistent with the proposed dissociation mechanisms for the two product speed regimes. Large values for the low and high rank in-plane orientation parameters are reported. These are believed to be the first example of a polyatomic system where these effects are found to be of the same order of magnitude as the angular momentum alignment.
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Affiliation(s)
- M Brouard
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
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119
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Brouard M, Quadrini F, Vallance C. The photodissociation dynamics of OCS at 248nm: The S(PJ3) atomic angular momentum polarization. J Chem Phys 2007; 127:084305. [PMID: 17764246 DOI: 10.1063/1.2757619] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dissociation of OCS has been investigated subsequent to excitation at 248 nm using velocity map ion imaging. Speed distributions, speed dependent translational anisotropy parameters, and the atomic angular momentum orientation and alignment are reported for the channel leading to S((3)P(J)). The speed distributions and beta parameters are in broad agreement with previous work and show behavior that is highly sensitive to the S-atom spin-orbit state. The data are shown to be consistent with the operation of at least two triplet production mechanisms. Interpretation of the angular momentum polarization data in terms of an adiabatic picture has been used to help identify a likely dissociation pathway for the majority of the S((3)P(J)) products, which strongly favors production of J=2 fragment atoms, correlated, it is proposed, with rotationally hot and vibrationally cold CO cofragments. For these fragments, optical excitation to the 2 (1)A(') surface is thought to constitute the first step, as for the singlet dissociation channel. This is followed by crossing, via a conical intersection, to the ground 1 (1)A(') state, from where intersystem crossing occurs, populating the 1 (3)A(')1 (3)A(")((3)Pi) states. The proposed mechanism provides a qualitative rationale for the observed spin-orbit populations, as well as the S((3)P(J)) quantum yield and angular momentum polarization. At least one other production mechanism, leading to a more statistical S-atom spin-orbit state distribution and rotationally cold, vibrationally hot CO cofragments, is thought to involve direct excitation to either the (3)Sigma(-) or (3)Pi states.
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Affiliation(s)
- M Brouard
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom.
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120
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Kłos J, Aoiz FJ, Verdasco JE, Brouard M, Marinakis S, Stolte S. Fully quantum state-resolved inelastic scattering between He and NO(XΠ2). J Chem Phys 2007; 127:031102. [PMID: 17655424 DOI: 10.1063/1.2756826] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Quantum mechanical close-coupling calculations have been used to obtain fully quantum state-resolved differential cross sections and opacity functions for the rotationally inelastic collisions of NO(X (2)Pi) with He at collision energies of 63 and 147 meV using the most recent ab initio potential energy surfaces of Kłos et al. [J. Chem. Phys. 112, 2195 (2000)]. Double peaks observed in the Lambda-doublet resolved differential cross sections are shown to be related to the presence of analogous peaks in the corresponding opacity functions. These structures can be linked directly to a specific expansion term in the potential, and reflect the fact that NO is not quite homonuclear.
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Affiliation(s)
- J Kłos
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain
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121
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Iribarren J, Jimenez J, Brouard M, Galvan R, Lorente L, Perez R, Alarco B, Diaz M, Malaga J, Huidobro S, Martinez R, Mora M. Complement activation and excessive bleeding in cardiopulmonary bypass surgery. Crit Care 2007. [PMCID: PMC4095309 DOI: 10.1186/cc5416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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122
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Jimenez J, Iribarren J, Brouard M, Barrios Y, Raya J, Lorente L, Perez R, Garcia C, Martinez J, Martinez R, Mora M. Role of plasminogen activator inhibitor-1 polymorphism on the development of vasoplegic syndrome associated with cardiopulmonary bypass. Crit Care 2007. [PMCID: PMC4095308 DOI: 10.1186/cc5415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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123
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Iribarren J, Jimenez J, Brouard M, Lorenzo J, Perez R, Lorente L, Nuñez C, Lorenzo L, Henry C, Martinez R, Mora M. Vasoplegic syndrome after cardiopulmonary bypass surgery – associated factors and clinical outcomes: a nested case-control study. Crit Care 2007. [PMCID: PMC4095307 DOI: 10.1186/cc5414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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124
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Brouard M, Jimenez J, Iribarren J, Lorente L, Perez R, Santana M, Milena A, Castedo J, Santacreu R, Martinez R, Mora M. Impact of body mass index on postoperative bleeding in cardiopulmonary bypass. Crit Care 2007. [PMCID: PMC4095310 DOI: 10.1186/cc5417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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125
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Aoiz FJ, Brouard M, Eyles CJ, Castillo JF, Sáez Rábanos V. Cumulative reaction probabilities: A comparison between quasiclassical and quantum mechanical results. J Chem Phys 2006; 125:144105. [PMID: 17042577 DOI: 10.1063/1.2353837] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This article presents a quasiclassical trajectory (QCT) method for determining the cumulative reaction probability (CRP) as a function of the total energy. The method proposed is based on a discrete sampling using integer values of the total and orbital angular momentum quantum numbers for each trajectory and on the development of equations that have a clear counterpart in the quantum mechanical (QM) case. The calculations comprise cumulative reaction probabilities at a given total angular momentum J, as well as those summed over J. The latter are used to compute QCT rate constants. The method is illustrated by comparing QCT and exact QM results for the H+H2, H+D2, D+H2, and H+HD reactions. The agreement between QCT and QM results is very good, with small discrepancies between the two data sets indicating some genuine quantum effects. The most important of these involves the value of the CRP at low energies which, due to the absence of tunneling, is lower in the QCT calculations, causing the corresponding rate constants to be smaller. The second is the steplike structure that is clearly displayed in the QM CRP for J = 0, which is much smoother in the corresponding QCT results. However, when the QCT density of reactive states, i.e., the derivatives of the QCT CRP with respect to the energy, is calculated, a succession of maxima and minima is obtained which roughly resembles those found in the QM calculations, although the latter are considerably sharper. The analysis of the broad peaks in the QCT density of reactive states indicates that the distributions of collision times associated with the maxima are somewhat broader, with a tail extending to larger collision times, than those associated with the minima. In addition, the QM and QCT dynamics of the isotopic variants mentioned above are compared in the light of their CRPs. Issues such as the compliance of the QCT CRP with the law of microscopic reversibility, as well as the similarity between the CRPs for ortho and para species in the QM and QCT cases, are also addressed.
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Affiliation(s)
- F J Aoiz
- Departamento de Química Física, Facultad de Química, Universidad Complutense, 28040 Madrid, Spain.
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126
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Brouard M, Cireasa R, Clark AP, Groenenboom GC, Hancock G, Horrocks SJ, Quadrini F, Ritchie GAD, Vallance C. The photodissociation dynamics of ozone at 193nm: An O(D21) angular momentum polarization study. J Chem Phys 2006; 125:133308. [PMID: 17029461 DOI: 10.1063/1.2210009] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Polarized laser photolysis, coupled with resonantly enhanced multiphoton ionization detection of O(1D2) and velocity-map ion imaging, has been used to investigate the photodissociation dynamics of ozone at 193 nm. The use of multiple pump and probe laser polarization geometries and probe transitions has enabled a comprehensive characterization of the angular momentum polarization of the O(1D2) photofragments, in addition to providing high-resolution information about their speed and angular distributions. Images obtained at the probe laser wavelength of around 205 nm indicate dissociation primarily via the Hartley band, involving absorption to, and diabatic dissociation on, the B 1B2(3 1A1) potential energy surface. Rather different O(1D2) speed and electronic angular momentum spatial distributions are observed at 193 nm, suggesting that the dominant excitation at these photon energies is to a state of different symmetry from that giving rise to the Hartley band and also indicating the participation of at least one other state in the dissociation process. Evidence for a contribution from absorption into the tail of the Hartley band at 193 nm is also presented. A particularly surprising result is the observation of nonzero, albeit small values for all three rank K = 1 orientation moments of the angular momentum distribution. The polarization results obtained at 193 and 205 nm, together with those observed previously at longer wavelengths, are interpreted using an analysis of the long range quadrupole-quadrupole interaction between the O(1D2) and O2(1Deltag) species.
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Affiliation(s)
- M Brouard
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom.
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127
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Brouard M, Cireasa R, Clark AP, Preston TJ, Vallance C. The photodissociation dynamics of NO2 at 308nm and of NO2 and N2O4 at 226nm. J Chem Phys 2006; 124:64309. [PMID: 16483209 DOI: 10.1063/1.2166631] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Velocity-map ion imaging has been applied to the photodissociation of NO(2) via the first absorption band at 308 nm using (2 + 1) resonantly enhanced multiphoton ionization detection of the atomic O((3)P(J)) products. The resulting ion images have been analyzed to provide information about the speed distribution of the O((3)P(J)) products, the translational anisotropy, and the electronic angular momentum alignment. The atomic speed distributions were used to provide information about the internal quantum-state distribution in the NO coproducts. The data were found to be consistent with an inverted NO vibrational quantum-state distribution, and thereby point to a dynamical, as opposed to a statistical dissociation mechanism subsequent to photodissociation at 308 nm. Surprisingly, at this wavelength the O-atom electronic angular momentum alignment was found to be small. Probe-only ion images obtained under a variety of molecular-beam backing-pressure conditions, and corresponding to O atoms generated in the photodissociation of either the monomer, NO(2), or the dimer, N(2)O(4), at 226 nm, are also reported. For the monomer, where 226 nm corresponds to excitation into the second absorption band, the kinetic-energy release distributions are also found to indicate a strong population inversion in the NO cofragment, and are shown to be remarkably similar to those previously observed in the wavelength range of 193-248 nm. Mechanistic implications of this result are discussed. At 226 nm it has also been possible to observe directly O atoms from the photodissociation of the dimer. The O-atom velocity distribution has been analyzed to provide information about its production mechanism.
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Affiliation(s)
- M Brouard
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford, UK.
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128
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Jimenez Rivera J, Iribarren Sarrias J, Nassar I, Alarco B, Diaz M, Perez R, Garcia C, Malaga J, Lorente L, Serrano N, Brouard M, Martinez R, Mora M. Crit Care 2006; 10:P223. [DOI: 10.1186/cc4570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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129
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Abstract
The angular momentum polarization of atomic photofragments provides a detailed insight into the dynamics of the photodissociation process. In this article, the origins of electronic angular momentum polarization are introduced and experimental and theoretical methods for the measurement or calculation of atomic orientation and alignment parameters described. Many diatomic photodissociation systems are surveyed, in order to provide an overview both of the historical development of the field and of the most state-of-the-art contemporary studies.
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Affiliation(s)
- A P Clark
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK
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130
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Brouard M, Cireasa R, Clark AP, Quadrini F, Vallance C. The photodissociation dynamics of O2 at 193 nm: an O(3PJ) angular momentum polarization study. Phys Chem Chem Phys 2006; 8:5549-63. [PMID: 17136270 DOI: 10.1039/b612460g] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the following paper we present translational anisotropy and angular momentum polarization data for O((3)P(1)) and O((3)P(2)) products of the photodissociation of molecular oxygen at 193 nm. The data were obtained using polarized laser photodissociation coupled with resonantly enhanced multiphoton ionization and velocity-map ion imaging. Under the jet-cooled conditions employed, absorption is believed to be dominated by excitation into the Herzberg continuum. The experimental data are compared with previous experiments and theoretical calculations at this and other wavelengths. Semi-classical calculations performed by Groenenboom and van Vroonhoven [J. Chem. Phys, 2002, 116, 1965] are used to estimate the alignment parameters arising from incoherent excitation and dissociation and these are shown to agree qualitatively well with the available experimental data. Following the work of Alexander et al. [J. Chem. Phys, 2003, 118, 10566], orientation and alignment parameters arising from coherent excitation and dissociation are modelled more approximately by estimating phase differences generated subsequent to dissociation via competing adiabatic pathways leading to the same asymptotic products. These calculations lend support to the view that large values of the coherent alignment moments, but small values of the corresponding orientation moments, could arise from coherent excitation of (and subsequent dissociation via) parallel and perpendicular components of the Herzberg I, II and III transitions.
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Affiliation(s)
- M Brouard
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK.
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Bass MJ, Brouard M, Cireasa R, Clark AP, Vallance C. Imaging photon-initiated reactions: A study of the Cl(P3∕22)+CH4→HCl+CH3 reaction. J Chem Phys 2005; 123:94301. [PMID: 16164339 DOI: 10.1063/1.2009737] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The hydrogen or deuterium atom abstraction reactions between Cl((2)P(3/2)) and methane, or its deuterated analogues CD(4) and CH(2)D(2), have been studied at mean collision energies around 0.34 eV. The experiments were performed in a coexpansion of molecular chlorine and methane in helium, with the atomic Cl reactants generated by polarized laser photodissociation of Cl(2) at 308 nm. The Cl-atom reactants and the methyl radical products were detected using (2+1) resonantly enhanced multiphoton ionization, coupled with velocity-map ion imaging. Analysis of the ion images reveals that in single-beam experiments of this type, careful consideration must be given to the spread of reagent velocities and collision energies. Using the reactions of Cl with CH(4), CD(4), and CH(2)D(2), as examples, it is shown that the data can be fitted well if the reagent motion is correctly described, and the angular scattering distributions can be obtained with confidence. New evidence is also provided that the CD(3) radicals from the Cl+CD(4) reaction possess significant rotational alignment under the conditions of the present study. The results are compared with previous experimental and theoretical works, where these are available.
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Affiliation(s)
- M J Bass
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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132
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Brouard M, Burak I, Marinakis S, Rubio Lago L, Tampkins P, Vallance C. Product spin–orbit state resolved dynamics of the H+H2O and H+D2O abstraction reactions. J Chem Phys 2004; 121:10426-36. [PMID: 15549923 DOI: 10.1063/1.1809578] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The product state-resolved dynamics of the reactions H+H(2)O/D(2)O-->OH/OD((2)Pi(Omega);v',N',f )+H(2)/HD have been explored at center-of-mass collision energies around 1.2, 1.4, and 2.5 eV. The experiments employ pulsed laser photolysis coupled with polarized Doppler-resolved laser induced fluorescence detection of the OH/OD radical products. The populations in the OH spin-orbit states at a collision energy of 1.2 eV have been determined for the H+H(2)O reaction, and for low rotational levels they are shown to deviate from the statistical limit. For the H+D(2)O reaction at the highest collision energy studied the OD((2)Pi(3/2),v'=0,N'=1,A') angular distributions show scattering over a wide range of angles with a preference towards the forward direction. The kinetic energy release distributions obtained at 2.5 eV also indicate that the HD coproducts are born with significantly more internal excitation than at 1.4 eV. The OD((2)Pi(3/2),v'=0,N'=1,A') angular and kinetic energy release distributions are almost identical to those of their spin-orbit excited OD((2)Pi(1/2),v'=0,N'=1,A') counterpart. The data are compared with previous experimental measurements at similar collision energies, and with the results of previously published quasiclassical trajectory and quantum mechanical calculations employing the most recently developed potential energy surface. Product OH/OD spin-orbit effects in the reaction are discussed with reference to simple models.
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Affiliation(s)
- M Brouard
- The Department of Chemistry, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, United Kingdom.
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de Miranda MP, Aoiz FJ, Sáez-Rábanos V, Brouard M. Spatial distributions of angular momenta in quantum and quasiclassical stereodynamics. J Chem Phys 2004; 121:9830-43. [PMID: 15549856 DOI: 10.1063/1.1809117] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have recently reported a derivation of the relationship between the quantum and classical descriptions of angular momentum polarization [M. P. de Miranda and F. Javier Aoiz, Phys. Rev. Lett. 93, 083201 (2004)]. This paper presents a detailed account of the derivation outlined in that paper, and discusses the implications of the new results. These include (i) a new expression of the role of the uncertainty principle in the broadening of angular momentum distributions, (ii) the attribution of azimuthal fluctuations of angular momentum distributions to spatial quantum beats, (iii) the definition of a new Fourier transform of the density matrix, distinct from those suggested in the past, that provides an alternative view of how the quantum description of angular momentum polarization approaches the classical one in the correspondence principle limit, (iv) a prescription for the determination of a quasiclassical angular momentum distribution function that does not suffer from problems encountered with its purely classical counterpart, and (v) a description of how angular momentum distributions commonly visualized with recourse to the classical vector model can be depicted with exact and well-defined quantum mechanics.
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Bass MJ, Brouard M, Vallance C, Kitsopoulos TN, Samartzis PC, Toomes RL. The dynamics of the Cl+n-C4H10→HCl (v′,j′)+C4H9 reaction at 0.32 eV. J Chem Phys 2004; 121:7175-86. [PMID: 15473785 DOI: 10.1063/1.1792593] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Rotational state resolved center-of-mass angular scattering and kinetic energy release distributions have been determined for the HCl (v' = 0, j' = 0-6) products of the reaction of chlorine with n-butane using the photon-initiated reaction technique, coupled with velocity-map ion imaging. The angular and kinetic energy release distributions derived from the ion images are very similar to those obtained previously for the Cl plus ethane reaction. The angular distributions are found to shift from forward scattering to more isotropic scattering with increasing HCl rotational excitation. The kinetic energy release distributions indicate that around 30% of the available energy is channeled into internal excitation of the butyl radical products. The data analysis also suggests that H-atom abstraction takes place from both primary and secondary carbon atom sites, with the primary site producing rotationally cold, forward scattered HCl (v' = 0) products, and the secondary site yielding more isotropically scattered HCl (v' = 0) possessing higher rotational excitation. The mechanisms leading to these two product channels are discussed in the light of the present findings, and in comparison with studies of other Cl plus alkane reactions.
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Affiliation(s)
- M J Bass
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
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135
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Martinez-Haya B, Bass MJ, Brouard M, Vallance C, Torres I, Barr J. Photodissociation and multiphoton dissociative ionization processes in CH3S2CH3 at 193 nm studied using velocity-map imaging. J Chem Phys 2004; 120:11042-52. [PMID: 15268134 DOI: 10.1063/1.1742732] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Dissociation and ionization processes in dimethyl disulfide, CH(3)S(2)CH(3), induced by one- or two-photon absorption of 193 nm light, have been studied using velocity-map ion imaging. The analysis of the ion images of the CH(3)S(2) (+), CH(3)S(+), S(2) (+), and S(+) fragments has allowed the characterization of the scattering dynamics of some of the main photolysis and dissociative-ionization processes. In particular, the experiments corroborate the formation of electronically excited SCH(3)((2)A(1)) products in the 193 nm photodissociation of dimethyl disulfide seen in earlier studies, and show that laser ionization provides a very sensitive method for their detection. The data have also allowed determination of the recoil energy and angular distributions of the CH(3)S(2) (+) and CH(3)S(+) products of the two-photon dissociative-ionization of the CH(3)S(2)CH(3) molecule. The measured distributions for these products are consistent with the formation of a transient parent ion which dissociates after a substantial intramolecular rearrangement, possibly yielding the most stable isomeric forms of the fragments, namely CH(2)S(2)H(+) and CH(2)SH(+).
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Affiliation(s)
- B Martinez-Haya
- Departamento de Ciencias Ambientales, Universidad Pablo de Olavide, E-41013 Seville, Spain.
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Brouard M, Cireasa R, Clark AP, Preston TJ, Vallance C, Groenenboom GC, Vasyutinskii OS. O(3PJ) Alignment from the Photodissociation of SO2 at 193 nm. J Phys Chem A 2004. [DOI: 10.1021/jp049328v] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Brouard
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - R. Cireasa
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - A. P. Clark
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - T. J. Preston
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - C. Vallance
- The Department of Chemistry, University of Oxford, The Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, OX1 3QZ, United Kingdom
| | - G. C. Groenenboom
- Institute of Theoretical Chemistry, NSRIM, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | - O. S. Vasyutinskii
- Ioffe Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
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Brouard M, Marinakis S, Rubio Lago L, Quadrini F, Solaiman D, Vallance C, Aoiz FJ, Bañares L, Castillo JF. Cross-sections for the H + H2O → OH + H2and H + D2O → OD + HD abstraction reactions. Phys Chem Chem Phys 2004. [DOI: 10.1039/b409667c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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138
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Bass MJ, Brouard M, Vallance C, Kitsopoulos TN, Samartzis PC, Toomes RL. The dynamics of the Cl+C2H6→HCl(v′,j′)+C2H5 reaction at 0.24 eV: Is ethyl a spectator? J Chem Phys 2003. [DOI: 10.1063/1.1606444] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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139
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Brouard M, Clark AP, Vallance C, Vasyutinskii OS. Velocity-map imaging study of the O(3P)+N2 product channel following 193 nm photolysis of N2O. J Chem Phys 2003. [DOI: 10.1063/1.1579471] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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140
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Brouard M, Burak I, Marinakis S, Minayev D, O'Keeffe P, Vallance C, Aoiz FJ, Bañares L, Castillo JF, Zhang DH, Xie D, Yang M, Lee SY, Collins MA. Cross section for the H+H2O abstraction reaction: experiment and theory. Phys Rev Lett 2003; 90:093201. [PMID: 12689220 DOI: 10.1103/physrevlett.90.093201] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2002] [Indexed: 05/24/2023]
Abstract
The absolute value of the cross section for the abstraction reaction between fast H atoms and H2O has been determined experimentally at a mean collision energy of 2.46 eV. The OH population distribution at the same mean energy has also been determined. The new measurements are compared with state-of-the-art quantum mechanical and quasiclassical scattering calculations on the most recently developed potential energy surface.
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Affiliation(s)
- M Brouard
- The Physical and Theoretical Chemistry Laboratory, The Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom
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141
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Bass MJ, Brouard M, Clark AP, Vallance C, Martínez-Haya B. Angular momentum alignment of Cl(2P3/2) in the 308 nm photolysis of Cl2 determined using Fourier moment velocity-map imaging. Phys Chem Chem Phys 2003. [DOI: 10.1039/b210092d] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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142
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Brouard M, Burak I, Minayev D, O’Keeffe P, Vallance C, Aoiz FJ, Bañares L, Castillo JF, Zhang DH, Collins MA. The dynamics of the H+D2O→OD+HD reaction at 2.5 eV: Experiment and theory. J Chem Phys 2003. [DOI: 10.1063/1.1528896] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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August J, Brouard M, Docker MP, Milne CJ, Simons JP, Lavi R, Rosenwaks S, Schwartz-Lavi D. Photodissociation dynamics of tert-butyl nitrite (S2) and tert-butyl hydroperoxide at 248-250 nm. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100330a030] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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145
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Brouard M, Duxon SP, Enriquez PA, Sayos R, Simons JP. Velocity-aligned photofragment dynamics: Stereodynamics in the reaction oxygen atom(1D) + nitrous oxide .fwdarw. nitric oxide + nitric oxide. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100174a028] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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146
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Brouard M, Lambert HM, Short J, Simons JP. Product State-Resolved Stereodynamics of the Reaction O(1D) + CH4 →OH + CH3. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100037a001] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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147
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Brouard M, Lightfoot PD, Pilling MJ. Observation of equilibration in the system atomic hydrogen + ethylene .dblharw. ethyl. The determination of the heat of formation of ethyl radical. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100275a019] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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148
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Brouard M, Macpherson MT, Pilling MJ. Experimental and RRKM modeling study of the methyl + hydrogen atom and deuterium atom reactions. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100347a037] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Affiliation(s)
- Mark Brouard
- The Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, U.K
| | - Patrick O'Keeffe, and
- The Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, U.K
| | - Claire Vallance
- The Physical and Theoretical Chemistry Laboratory, The University of Oxford, South Parks Road, Oxford, OX1 3QZ, U.K
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