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1.
BMC Oral Health ; 24(1): 566, 2024 May 14.
Article de Anglais | MEDLINE | ID: mdl-38745286

RÉSUMÉ

PURPOSE: Our study aimed to evaluate the long-term concordance and acceptance when using powered devices for everyday oral hygiene routine and gingival health in patients showing papillary bleeding. PATIENTS AND METHODS: Thirty-one participants were recruited at the dental clinic of the University Hospital of Cologne, Germany, over a 6-week duration. At baseline, a standard dental check-up was performed, including oral hygiene indices and documentation of oral hygiene devices used. The study consisted of two consecutive phases: the first (motivational trial) was designed to prove the effectiveness and safety of a microdroplet device and a powered toothbrush compared to dental floss and a manual toothbrush over a period of 4 weeks. The second (observational) phase began with all participants receiving the powered oral homecare devices. Participants were able to use their oral hygiene measures of choice over an unsupervised period of 1 year. All participants were then rescheduled for a routine dental check-up, where oral hygiene indices and oral hygiene devices used were reevaluated. RESULTS: After 1 year, 93.3% of participants stated they performed interdental cleaning on a regular basis (baseline 60.0%). The percentage using a powered toothbrush increased from 41.9% (baseline) to 90.0% after 1 year. Oral hygiene parameters had improved after both the motivational trial and observational phases compared to baseline (papillary bleeding index p = .000; Rustogi Modified Navy Plaque Index p < .05; Quigley-Hein Index p = .000). CONCLUSION: In the long term, participants preferred using powered oral hygiene devices over the gold standard dental floss and manual toothbrush. Improved oral hygiene parameters after 1 year may indicate implementation of newly acquired oral-hygiene skills during the 4-week instruction phase.


Sujet(s)
Dispositifs d'hygiène buccodentaire à usage domestique , Hygiène buccodentaire , Brossage dentaire , Humains , Mâle , Femelle , Hygiène buccodentaire/instrumentation , Hygiène buccodentaire/enseignement et éducation , Adulte , Brossage dentaire/instrumentation , Études longitudinales , Adulte d'âge moyen , Indice parodontal , Indice d'hygiène buccale , Sujet âgé , Gingivite/prévention et contrôle
2.
J Fr Ophtalmol ; 47(6): 104183, 2024 Jun.
Article de Français | MEDLINE | ID: mdl-38593489
3.
Anaesthesia ; 78(9): 1129-1138, 2023 09.
Article de Anglais | MEDLINE | ID: mdl-37340620

RÉSUMÉ

The aim of neuraxial analgesia is to achieve excellent pain relief with the fewest adverse effects. The most recently introduced technique for epidural analgesia maintenance is the programmed intermittent epidural bolus. In a recent study, we compared this with patient-controlled epidural analgesia without a background infusion and found that a programmed intermittent epidural bolus was associated with less breakthrough pain, lower pain scores, higher local anaesthetic consumption and comparable motor block. However, we had compared 10 ml programmed intermittent epidural boluses with 5 ml patient-controlled epidural analgesia boluses. To overcome this potential limitation, we designed a randomised, multicentre non-inferiority trial using 10 ml boluses in each group. The primary outcome was the incidence of breakthrough pain and total analgesic intake. Secondary outcomes included motor block; pain scores; patient satisfaction; and obstetric and neonatal outcomes. The trial was considered positive if two endpoints were met: non-inferiority of patient-controlled epidural analgesia with respect to breakthrough pain; and superiority of patient-controlled epidural analgesia with respect to local anaesthetic consumption. A total of 360 nulliparous women were allocated randomly to patient-controlled epidural analgesia-only or programmed intermittent epidural bolus groups. The patient-controlled group received 10 ml boluses of ropivacaine 0.12% with sufentanil 0.75 µg.ml-1 ; the programmed intermittent group received 10 ml boluses supplemented by 5 ml patient-controlled boluses. The lockout period was 30 min in each group and the maximum allowed hourly local anaesthetic/opioid consumption was identical between the groups. Breakthrough pain was similar between groups (11.2% patient controlled vs. 10.8% programmed intermittent, p = 0.003 for non-inferiority). Total ropivacaine consumption was lower in the PCEA-group (mean difference 15.3 mg, p < 0.001). Motor block, patient satisfaction scores and maternal and neonatal outcomes were similar across both groups. In conclusion, patient-controlled epidural analgesia is non-inferior to programmed intermittent epidural bolus if equal volumes of patient-controlled epidural analgesia are used to maintain labour analgesia and superior with respect to local anaesthetic consumption.


Sujet(s)
Analgésie péridurale , Analgésie obstétricale , Douleur paroxystique , Grossesse , Nouveau-né , Femelle , Humains , Anesthésiques locaux , Ropivacaïne , Douleur paroxystique/étiologie , Analgésiques , Analgésie péridurale/méthodes , Analgésie autocontrôlée/méthodes , Analgésie obstétricale/méthodes , Méthode en double aveugle
4.
GMS J Med Educ ; 37(7): Doc87, 2020.
Article de Anglais | MEDLINE | ID: mdl-33364366

RÉSUMÉ

Objective: Primary outcome of this retrospective study was the comparison of state examination results under simulated treatment conditions in times of Covid-19 versus patient treatment under non-pandemic conditions. Additionally, correlation analysis was performed between students' self- and examiners' assessment of the treatment results. Methods: Within 4 hours, 22 examinees each had to place a multi-surface adhesive anterior and posterior restoration, performed an endodontic treatment on a maxillary premolar and a periodontal debridement of one quadrant. All treatments were performed on a model fixed in a phantom head. Compliance with the prescribed hygiene and social distancing guidelines and self-assessment of the practical performance was part of the practical examination as well. One examiner per examination part evaluated anonymously the final results. The historical control was based on the exam results of a cohort from 2019. Mean values (standard deviation), non-parametric correlations (Spearman's Rho) and group comparisons (Mann-Whitney) were calculated for statistical analysis. Results: Examination results under simulated treatment conditions were significantly worse (p<0.05) than in the cohort that took their state exam in patients, with exception of the endodontic partial exam. The overall scores in restorative dentistry and periodontology of both groups, which include a structured theoretical examination, did not differ. The majority of the candidates rated their performance worse than the examiners, and there was no correlation between self- and third-party assessment. Conclusion: In the comparison of two years, a simulated practical examination without patients in restorative dentistry, endodontics and periodontology resulted in matchable results compared with an examination on patients. Equal conditions for the candidates resulting in better comparability and avoidance of ethical dilemmas of patient treatment under examination conditions could also be arguments towards a state examination under phantom conditions in the future.


Sujet(s)
COVID-19/épidémiologie , Enseignement dentaire/organisation et administration , Enseignement à distance/organisation et administration , Évaluation des acquis scolaires/statistiques et données numériques , Dentistes/enseignement et éducation , Enseignement dentaire/normes , Enseignement à distance/normes , Évaluation des acquis scolaires/normes , Endodontie/enseignement et éducation , Humains , Modèles anatomiques , Pandémies , SARS-CoV-2 , Auto-évaluation (psychologie) , Étudiant dentisterie
5.
Anaesthesia ; 75(12): 1635-1642, 2020 12.
Article de Anglais | MEDLINE | ID: mdl-32530518

RÉSUMÉ

The programmed intermittent epidural bolus technique has shown superiority to continuous epidural infusion techniques, with or without patient-controlled epidural analgesia for pain relief, reduced motor block and patient satisfaction. Many institutions still use patient-controlled epidural analgesia without a background infusion, and a comparative study between programmed intermittent epidural bolus and patient-controlled epidural analgesia without a background infusion has not yet been performed. We performed a randomised, two-centre, double-blind, controlled trial of these two techniques. The primary outcome was the incidence of breakthrough pain requiring a top-up dose by an anaesthetist. Secondary outcomes included: motor block; pain scores; patient satisfaction; local anaesthetic consumption; and obstetric and neonatal outcomes. We recruited 130 nulliparous women who received initial spinal analgesia, and then epidural analgesia was initiated and maintained with either programmed intermittent epidural bolus or patient-controlled epidural analgesia using ropivacaine 0.12% with sufentanil 0.75 µg·ml-1 . The programmed intermittent epidural bolus group had a programmed bolus of 10 ml every hour, with on-demand patient-controlled epidural analgesia boluses of 5 ml with a 20 min lockout, and the patient-controlled epidural analgesia group had a 5 ml bolus with a 12 min lockout interval; the potential maximum volume per hour was the same in both groups. The patients in the programmed intermittent epidural bolus group had less frequent breakthrough pain compared with the patient-controlled epidural analgesia group, 7 (10.9%) vs. 38 (62.3%; p < 0.0001), respectively. There was a significant difference in motor block (modified Bromage score ≤ 4) frequency between groups, programmed intermittent epidural bolus group 1 (1.6%) vs. patient-controlled epidural analgesia group 8 (13.1%); p = 0.015. The programmed intermittent epidural bolus group had greater local anaesthetic consumption with fewer patient-controlled epidural analgesia boluses. Patient satisfaction scores and obstetric or neonatal outcomes were not different between groups. In conclusion, we found that a programmed intermittent epidural bolus technique using 10 ml programmed boluses and 5 ml patient-controlled epidural analgesia boluses was superior to a patient-controlled epidural analgesia technique using 5 ml boluses and no background infusion.


Sujet(s)
Analgésie péridurale/méthodes , Analgésie obstétricale/méthodes , Analgésie autocontrôlée/méthodes , Adulte , Méthode en double aveugle , Femelle , Humains , Grossesse
6.
J Chem Phys ; 150(18): 184303, 2019 May 14.
Article de Anglais | MEDLINE | ID: mdl-31091894

RÉSUMÉ

Reliable ozone spectral data consistent over several spectral ranges are a challenge for both experiment and theory. We present ab initio calculations for strong lines that lead to consistent results from the microwave to mid-infrared regions. The results agree well with established microwave line lists and our new measurements in the fundamental and first overtone regions of ozone at 5 and 10 µm. The calculations and their agreement to within 1% with measurements provide an important step toward consistent and accurate spectroscopic ozone data. The results imply that actual databases need to be corrected by about 3% in the corresponding mid-infrared spectral intervals. Appropriate recommendations for the consistency of strong line intensities of the ozone molecule in microwave, 10 and 5 µm ranges, in HITRAN (HIgh-resolution TRANsmittance and molecular apbsorption) and GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphériques) databases are suggested.

7.
Int J Dent Hyg ; 16(1): 36-47, 2018 Feb.
Article de Anglais | MEDLINE | ID: mdl-28836329

RÉSUMÉ

OBJECTIVE: The aim of this systematic review was to give the best available evidence on the impact of professional tooth cleaning (PTC) and scaling and root planing (SRP) on oral halitosis in patients with periodontal diseases. MATERIAL AND METHODS: Three databases were screened for relevant studies. Only randomized controlled trials (RCTs) or controlled clinical trials (CCT) were included. The primary outcome in all included studies was volatile sulphur compounds (VSC) measured by Halimeter or OralChroma and organoleptic scores as secondary outcome. Only studies investigating healthy adults except for periodontitis or gingivitis were included. The considered intervention strategies were professional tooth cleaning and non-surgical periodontal treatment. For both strategies, additional oral hygiene instructions (OHI) were possible. Two independent reviewers performed the study selection and quality assessment. SEARCH RESULTS: After abstract and title screening and subsequent full-text reading of potential papers, a placebo-controlled RCT could not be found. However, eight studies or particular arms used PTC or SRP as sole interventions and were included in this review. All trials or study arms included showed a positive effect on VSC levels or organoleptic scores after intervention. CONCLUSIONS: Based on best available evidence, PTC and SRP in combination with oral hygiene instructions reduced VSC values in patients with oral halitosis and/or periodontal diseases, independent of tongue cleaning and the use of mouth rinses.


Sujet(s)
Polissage dentaire , Détartrage dentaire , Halitose/thérapie , Surfaçage radiculaire , Tests d'analyse de l'haleine , Halitose/étiologie , Humains , Sulfure d'hydrogène/analyse , Maladies parodontales/complications , Composés organiques volatils
8.
Int J Dent Hyg ; 16(2): e31-e37, 2018 May.
Article de Anglais | MEDLINE | ID: mdl-28544397

RÉSUMÉ

OBJECTIVES: To compare in a randomized clinical trial the efficacy of a high-velocity microdroplet device for interdental cleaning vs dental floss at reducing plaque and gingivitis. METHODS: Sixty participants with an irregular interdental home cleaning regime were randomly assigned to use either a microdroplet device (n=40, test) or dental floss (n=20, control) for 4 weeks. At baseline and reassessment, the papilla bleeding index, the modified proximal plaque index and the amount of gingival crevicular fluid (GCF) were recorded. At the second appointment, participants completed a questionnaire regarding their assigned interdental cleaning option. The process quality of this investigator-initiated trial was ensured by independent scientific observers and media representatives. RESULTS: Improvement in the interdental cleaning routine reduced gingivitis in both groups (P<.05). The microdroplet device was more effective at reducing plaque (P=.003). The GCF amount remained the same in both groups. Comfort of use was greater with the microdroplet device. However, self-reported effectiveness was superior with dental floss. About 85% of participants using the microdroplet device said they would continue daily use. CONCLUSION: Improving the interdental cleaning routine with the microdroplet device or dental floss reduced gingivitis and plaque in both groups. Acceptance regarding comfort of use was higher with the microdroplet device. Dental floss remained the first choice for narrow interdental spaces, yet the microdroplet device offers an effective and well-accepted alternative for patients who fail the proper flossing routine.


Sujet(s)
Plaque dentaire/prévention et contrôle , Gingivite/thérapie , Hygiène buccodentaire/instrumentation , Autosoins , Adulte , Dispositifs d'hygiène buccodentaire à usage domestique , Indice de plaque dentaire , Conception d'appareillage , Femelle , Allemagne , Exsudat gingival/composition chimique , Humains , Mâle , Observance par le patient , Satisfaction des patients , Méthode en simple aveugle , Enquêtes et questionnaires , Résultat thérapeutique
9.
Oral Dis ; 23(4): 464-470, 2017 May.
Article de Anglais | MEDLINE | ID: mdl-27976483

RÉSUMÉ

OBJECTIVE: Parkinson's disease (PD) adversely affects oral health (OH). However, the informative value of xerostomia compared to objective parameters and its impact on quality of life (QoL) are still unclear. This study aimed to explore whether xerostomia correlates with hyposalivation and to define its impact on OH-related QoL. MATERIALS AND METHODS: Whole stimulated saliva (WSS) was collected from 30 patients with PD and 30 matched healthy controls. Objective parameters (community periodontal index of treatment needs, plaque/gingivitis index, mucosa situation and cheilitis angularis) and questionnaires (German Oral Health Impact Profile [OHIPG]-14, visual analogue scale [VAS], xerostomia [yes/no] and the Unified Parkinson's Disease Rating Scale-II) were assessed. RESULTS: Eighty-seven per cent of patients with PD showed hyposalivation vs 50% of controls (P = 0.001); 50% of patients with PD reported xerostomia, and none of controls (P < 0.001). The OHIPG-14 was impaired in patients with PD compared to controls (P < 0.001), PD patients with xerostomia reported mean VAS values of 4.1 (s.d.: 2.2). WSS did not correlate with VAS values. CONCLUSIONS: Half of the patients with PD reported xerostomia and underestimated their xerostomic status, with higher probability than healthy controls. WSS did not reflect the grade of xerostomia. Patients with PD suffered from impaired OH-related QoL. Dental teams should not overlook these oral health risks.


Sujet(s)
Maladie de Parkinson/complications , Qualité de vie , Xérostomie/étiologie , Adulte , Sujet âgé , Études cas-témoins , Femelle , Indicateurs d'état de santé , Humains , Mâle , Adulte d'âge moyen , Xérostomie/diagnostic , Xérostomie/épidémiologie
10.
Environ Sci Technol ; 50(15): 8188-95, 2016 08 02.
Article de Anglais | MEDLINE | ID: mdl-27351274

RÉSUMÉ

The present study describes new procedures to obtain at millimeter resolution the spatial distribution of nitrite and nitrate in porewaters, combining diffusive equilibrium in thin films (DET), colorimetry and hyperspectral imagery. Nitrite distribution can be easily achieved by adapting the well-known colorimetric method from Griess (1879) and using a common flatbed scanner with a limit of detection about 1.7 µmol L(-1). Nitrate distribution can be obtained after reduction into nitrite by a vanadium chloride reagent. However, the concentration of vanadium chloride used in this protocol brings coloration with a wide spectral signature that creates interference only deconvolvable by imaging treatment from an entire visible spectrum for each pixel (spectral analysis). This can be achieved by hyperspectral imaging. The protocol retained in the present study allows obtaining a nitrite/nitrate image with micromolar limit of detection. The methods were applied in sediments from the Loire Estuary after different treatments and allowed to precisely describe two-dimensional millimeter features. The present technique adds to the combination of gel-colorimetry and hyperspectral imagery a very promising new application of wide interest for environmental issues in the context of early diagenesis and benthic fluxes.


Sujet(s)
Nitrites , Eau , Colorimétrie , Nitrates , Polluants chimiques de l'eau
11.
Vet Microbiol ; 180(1-2): 142-5, 2015 Oct 22.
Article de Anglais | MEDLINE | ID: mdl-26298858

RÉSUMÉ

Ten cattle farms located in an area with a recent history of poultry botulism outbreaks were investigated to evaluate the occurrence of toxigenic C. botulinum in healthy cattle. Environmental samples in the 10 cattle farms and bovine fecal contents in farms with a confirmed environmental contamination were collected. Detection of C. botulinum toxin genes C, D, C/D, D/C and E was performed using real-time PCR. 4.9% (7/143) of the environmental samples collected in the 10 investigated cattle farms were positive for C. botulinum type C/D. Theses samples (boot-swabs in stalls and on pasture and water of a stream) were collected in 3 different farms. One cow dung sample and 3 out of 64 fecal contents samples collected in a single farm were also positive for C. botulinum type C/D. This study demonstrates that cattle are probably indirectly contaminated via poultry botulism in the area and that they can be intermittent carrier of C. botulinum type C/D after poultry botulism outbreaks in mixed farms.


Sujet(s)
Botulisme/médecine vétérinaire , Clostridium botulinum/isolement et purification , Épidémies de maladies/médecine vétérinaire , Microbiologie de l'environnement , Maladies de la volaille/microbiologie , Animaux , Botulisme/épidémiologie , Botulisme/microbiologie , Bovins , Fèces/microbiologie , Femelle , Volaille , Maladies de la volaille/épidémiologie
12.
Phys Rev Lett ; 113(14): 143002, 2014 Oct 03.
Article de Anglais | MEDLINE | ID: mdl-25325639

RÉSUMÉ

Since the discovery of anomalies in ozone isotope enrichment, several fundamental issues in the dynamics linked to the shape of the potential energy surface in the transition state region have been raised. The role of the reeflike structure on the minimum energy path is an intricate question previously discussed in the context of chemical experiments. In this Letter, we bring strong arguments in favor of the absence of a submerged barrier from ultrasensitive laser spectroscopy experiments combined with accurate predictions of highly excited vibrations up to nearly 95% of the dissociation threshold.

13.
Z Orthop Unfall ; 148(4): 429-35, 2010 Aug.
Article de Allemand | MEDLINE | ID: mdl-20714983

RÉSUMÉ

INTRODUCTION: Despite controversial discussions, hip resurfacing at the moment seems to be the most bone-sparing surgical procedure of the femoral bone when implanting hip endoprostheses. Main risks are septic and aseptic loosening and necroses of the coxal end of the femoral bone mainly influenced by the periprosthetic allocation of bone cement. Because of a lack of radiation transparency of the hip resurfacing implant, this cement allocation cannot be sufficiently evaluated by common radiological procedures. A pilot study was conducted to describe and validate the macromechanical interdigitation of bone cement with spongy bone of anatomic specimens compared to artificial bone models and to evaluate whether artificial bones may be used for further interdigitation studies of different implantation techniques. METHODS: Plastic models of polyoxymethylene (POM) according to the inside geometry of the Metasul Durom hip prosthesis were implanted on ex vivo femora (n = 14) versus artificial bone models (n = 24) (Sawbones) of three different spongy densities (0.16; 0.20; 0.32 g/cm(3)) (each n = 8) in a clinically standardised surgical procedure and reproduced by highly resolving computed tomography. Afterwards a computer-based analysis of the cement allocation was accomplished. RESULTS: It could be shown that the Sawbones of the lower spongy densities (0.16 and 0.20 g/cm(3)) were similar to the ex vivo femora regarding the bone penetration of cement. No significant differences could be shown regarding interdigitation. According to our data, both groups of Sawbones may be used for further studies.


Sujet(s)
Arthroplastie prothétique de hanche/méthodes , Ciments osseux/usage thérapeutique , Analyse de panne d'appareillage , Fémur/anatomopathologie , Prothèse de hanche , Modèles anatomiques , Complications postopératoires/anatomopathologie , Conception de prothèse , Résines synthétiques , Sujet âgé , Sujet âgé de 80 ans ou plus , Densité osseuse/physiologie , Infographie , Femelle , Humains , Traitement d'image par ordinateur , Techniques in vitro , Mâle , Adulte d'âge moyen , Projets pilotes , Logiciel , Tomodensitométrie
14.
Z Orthop Unfall ; 148(5): 554-8, 2010 Sep.
Article de Allemand | MEDLINE | ID: mdl-20387205

RÉSUMÉ

BACKGROUND: The efficiency and success of computer-assisted fluoroscopic navigation systems mainly depend on the quality of the process of image acquisition: obtaining the correct view of anatomic structures, relative orientation of multiplanar X-ray images and the necessary amount of radiation dose. These systems may be optimised by using a system called zero-dose c-arm navigation (ZDCAN). We investigate whether the available computer-assisted systems may be used to navigate the c-arm before image acquisition to obtain X-ray images with maximised accuracy and minimal radiation exposure. METHODS: Based on position data of an optical tracking system combined with statistical deformable bone models, ZDCAN is able to generate a real-time preview of expected X-ray images of the lower extremities without using radiation. We performed a cadaver study on six full-body specimens comparing the zero-dose approach to conventional positioning of the c-arm in order to evaluate efficiency and accuracy. Eight users acquired two perpendicular X-ray images of the hip, the knee and the femoral diaphysis. RESULTS: The number of X-ray images required to get a satisfying picture could be reduced to seven using the zero-dose approach; the conventional approach needed 11 images. The mean time did not differ significantly. Regarding the image quality, using ZDCAN quasi-orthogonality could be reached while the conventional approach showed a large variation of the relative orientation. CONCLUSION: Using ZDCAN, the amount of radiation can be reduced by requiring less X-ray images as well as reaching better accuracy.


Sujet(s)
Charge corporelle , Dose de rayonnement , Radioprotection/méthodes , Tomodensitométrie/méthodes , Imagerie du corps entier , Cadavre , Humains
15.
Phys Chem Chem Phys ; 10(20): 2925-46, 2008 May 28.
Article de Anglais | MEDLINE | ID: mdl-18473041

RÉSUMÉ

Weak vibrational bands of (16)O(3) could be detected in the 5850-7030 cm(-1) spectral region by CW-cavity ring down spectroscopy using a set of fibered DFB diode lasers. As a result of the high sensitivity (noise equivalent absorption alpha(min) approximately 3 x 10(-10) cm(-1)), bands reaching a total of 16 upper vibrational states have been previously reported in selected spectral regions. In the present report, the analysis of the whole investigated region is completed by new recordings in three spectral regions which have allowed: (i) a refined analysis of the nu(1) + 3nu(2) + 3nu(3) band from new spectra in the 5850-5900 cm(-1) region; (ii) an important extension of the assignments of the 2nu(1)+5nu(3) and 4nu(1) + 2nu(2) + nu(3) bands in the 6500-6600 cm(-1) region, previously recorded by frequency modulation diode laser spectroscopy. The rovibrational assignments of the weak 4nu(1) + 2nu(2) + nu(3) band were fully confirmed by the new observation of the 4nu(1) + 2nu(2) + nu(3)- nu(2) hot band near 5866.9 cm(-1) reaching the same upper state; (iii) the observation and modelling of three A-type bands at 6895.51, 6981.87 and 6990.07 cm(-1) corresponding to the highest excited vibrational bands of ozone detected so far at high resolution. The upper vibrational states were assigned by comparison of their energy values with calculated values obtained from the ground state potential energy surface of (16)O(3). The vibrational mixing and consequently the ambiguities in the vibrational labelling are discussed. For each band or set of interacting bands, the spectroscopic parameters were determined from a fit of the corresponding line positions in the frame of the effective Hamiltonian (EH) model. A set of selected absolute line intensities was measured and used to derive the parameters of the effective transition moment operator. The exhaustive review of the previous observations gathered with the present results is presented and discussed. It leads to a total number of 3863 energy levels belonging to 21 vibrational states and corresponding to 7315 transitions. In the considered spectral region corresponding to up to 82% of the dissociation energy, the increasing importance of the "dark" states is illustrated by the occurrence of frequent rovibrational perturbations and the observation of many weak lines still unassigned.


Sujet(s)
Ozone/composition chimique , Spectroscopie proche infrarouge/méthodes , Analyse spectrale/méthodes , Ozone/analyse , Sensibilité et spécificité , Analyse spectrale/instrumentation , Vibration
16.
J Mol Spectrosc ; 206(1): 1-13, 2001 Mar.
Article de Anglais | MEDLINE | ID: mdl-11281679

RÉSUMÉ

Using a Fourier transform spectrometer, we have recorded the spectra of the (18)O(3) species of ozone in the region 1300-3100 cm(-1), with a resolution of 0.003 cm(-1). The large product pathlength x pressure enable us to record 18 bands, 14 for the first time. The analysis has been performed using effective Hamiltonians for polyads of strongly interacting states for ozone, accounting for Coriolis and anharmonic resonances. The spectral parameters are derived for 16 vibrational states, including the two "dark" states (040) and (130). Various resonances are studied through the mixing coefficients of rovibrational wavefunctions. Systematic intensity measurements allow determination of transition moment parameters for 16 bands. Finally, a complete list of all transitions from 1300 to 3100 cm(-1), with cutoffs 10(-26) cm(-1)/mol cm(-2) (296 K), is calculated. Copyright 2001 Academic Press.

17.
J Mol Spectrosc ; 206(1): 14-26, 2001 Mar.
Article de Anglais | MEDLINE | ID: mdl-11281680

RÉSUMÉ

The analysis of high-resolution spectra of (18)O(3) is reported here for the range 3100-5000 cm(-1). Eight sets of polyads, corresponding to eight newly observed bands and accounting for resonance perturbations with eight other "dark" states, are analyzed for the first time. These analyses lead to eight sets of spectroscopic parameters, band centers, and rotational and centrifugal distortion constants, as well as transition moment parameters. In addition, various resonances are studied and compared to the similar ones for (16)O(3). This study allows us to check the work on (16)O(3) and to confirm that the accidentally strong high-order Deltav=8 anharmonic resonance for bands 5 nu(3)<-->3nu(1)+nu(2)+nu(3) was an exceptional case of the major isotopic species. Copyright 2001 Academic Press.

19.
J Mol Spectrosc ; 205(1): 43-53, 2001 Jan.
Article de Anglais | MEDLINE | ID: mdl-11148106

RÉSUMÉ

Two hundred ninety experimental absolute intensities of nu(1) and nu(3) transitions of ozone have been measured, with good accuracy (<2%). They are used to derive the transition-moment parameters for these bands. The agreement between our observed and calculated line intensities is satisfactory. This work shows that the intensities of these two bands are on average 4% smaller than those used in the literature. In addition, 20 intensities of the nu(2) + nu(3) - nu(2) band confirm this value. Also, 42 line intensities of the 2nu(1)-nu(3) band are reported. Copyright 2001 Academic Press.

20.
J Mol Spectrosc ; 198(1): 57-76, 1999 Nov.
Article de Anglais | MEDLINE | ID: mdl-10527781

RÉSUMÉ

The effective ground state potential energy function of the ozone molecule near the C(2v) equilibrium configuration was obtained in a least-squares fit to the largest sample of experimental, high-resolution vibration-rotation data used for this purpose so far. The fitting is based on variational calculations carried out with the extended Morse Oscillator Rigid Bender Internal Dynamics model. The potential function is expanded in Morse-type functions of the stretching variables and in cosine of the bending angle. The present calculation produces results in significantly better agreement with experiment than previous determinations of the potential energy surface, and the energies predicted with the new surface are sufficiently accurate to be useful for the assignment of new high-resolution spectra. The rms (root-mean-square) deviation of the fit of rovibrational data up to J = 5 is 0.02 cm(-1). For the set of all 60 band centers of the (16)O(3) molecule included in the Atlas of Ozone Line Parameters, the rms deviation is 0.025 cm(-1), and for all band centers determined so far from high-resolution spectra, including those recently observed and assigned in Reims corresponding to highly excited stretching and bending vibrations (v(1) + v(2) + v(3) = 6), the rms deviation is 0.1 cm(-1). The "dark states" that produce resonance perturbations in the observed bands are described with experimental accuracy up to the (v(1)v(2)v(3)) = (080) state. Extrapolation tests demonstrate the predictive power of the potential function obtained: rotational extrapolation up to J = 10 for the 11 lowest vibrational states results in an rms deviation of 0.06cm(-1). Also, vibrational energies measured by low-resolution Raman spectroscopy (which were not included in the input data for the fit) are calculated within the experimental accuracy (rms = 1.6 cm(-1)) of the experimental values up to the dissociation limit. The statistical analysis suggests that the accuracy of the equilibrium geometry and force constants of the molecule is considerably improved relative to previous determinations. The long-range behavior of the fitted potential at the dissociation limit O(3) --> O(2) + O shows very good agreement with experimental data. The new potential energy surface was used to predict the band centers of the isotopomers (17)O(3) and (18)O(3). Copyright 1999 Academic Press.

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