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BP’s Deepwater Horizon oil spill in April 2010 was a major test of the National Incident Management System (NIMS), which the United States federal government mandates for response to all disasters. At the time, this disaster was perhaps the greatest event in scope and duration under NIMS disaster management guidelines since they were revised in 2008 (the third edition was published in 2017). Ten years later, NIMS provides procedures for operating a joint information center (JIC), but still offers no guidelines for ethical communication. This case study examines the ethical implications of 178 news releases distributed by the Deepwater Horizon Incident JIC. Qualitative analysis found that communication was conducted in an open, ethical manner, with few exceptions. Conflicts emerged, however, that may have compromised ethical standards. The authors conclude with recommendations to inform ethical decision making by JIC communicators.

Disaster and emergency crisis management communication refers to the sorts of crisis, often called disaster because of the amount of property damage and loss of life that can occur. With its focus on prevention and mitigation, this genre of crisis communication requires thorough, science-based understanding of knowable disasters. Management plans need to be developed and implemented to minimize damage. Communication protocols should balance information and persuasion to help risk bearers, those individuals likely to be adversely affected by disaster, understand the disaster potential, the prevention measures to be implemented, and be motivated to act as recommended (or commanded) by the emergency management team. Thus, through monitoring, a vulnerable community can be alerted to a pending hurricane. Weather forecasters track the storm, and emergency managers put into place the prevention and response protocols. Such protocols might include boarding up windows, storing lawn equipment so it will not blow, having emergency food, water, and batteries, and knowing whether to shelter-in-place or evacuate as ordered. If evacuation is ordered, it needs to follow a management plan so that streets and roads are not blocked that prevent the most vulnerable from evacuating.

Purpose – The purpose of this paper is to explicate chaos theory metaphorically from a social science perspective to expand upon a relatively new theoretical framework for crisis communication in the public sector. Using the 2002 Washington, DC, area sniper shootings as a case study, the author unravel chaos theory in terms of a public safety crisis that required crisis communication by government officials. Design/methodology/approach – The author analysed front-page coverage in The Washington Post and The New York Times as well as CNN coverage during the three weeks of the sniper shootings, 2 October through 25 October. In total, 56 (69 per cent) of the newspaper stories were published in The Washington Post, and 78 news segments were used from CNN archives. Each story was reviewed for evidence of chaotic elements and crisis communication responses using a code sheet, and the resulting thematic analysis created a composite description of the case. Findings – This case exhibited the main characteristics of a chaotic system, including fractals, error of scale, bifurcation points, self-organisation, feedback, and strange attractors. The results describe how each element of chaos influenced the crisis communication efforts. Originality/value – To date, there is no known research on law enforcement's efforts in crisis communication during the DC sniper shootings. There is also limited research in chaos theory and crisis response. This research may aid in communication efforts during future public safety crises and disasters.

PurposeThe purpose of this study is to refine and expand an emerging US government communication model, the government communication decision wheel, by testing the differences between the communication practices of US public sector communicators working for non‐elected officials versus those employed by elected officials.Design/methodology/approachDrawing from surveys of 781 US government communicators, the study compares the communication practices and influences of government communicators working for elected officials versus non‐elected officials.FindingsThe study identifies four significant differences and five similarities in how the public sector environment affects non‐elected and elected officials’ communicators’ public relations practices.Research limitations/implicationsWhile the study and underlying model focus on US government communication, this study provides valuable theoretical insights. It supports the model's underlying premise that the public sector is unique from the private sector while also further refining the significant differences within the US government sector.Practical implicationsThis study helps US government communicators identify unique environmental attributes that affect communication activities in the public sector. It helps identify how these attributes affect communication practices within individual and collaborative contexts. Finally, it helps non‐governmental communicators and communicators outside of the US to understand how the attributes may affect communication practices when they collaborate with government communicators from the four levels of US government as well as with those who work for elected and non‐elected officials.Originality/valueDespite the critical importance of communication in the public sector, very little research focuses specifically on government communication outside of political communication. The findings provide valuable insights for practitioners and contribute to public relations theory development for the under‐researched public sector.

Public administration scholars often note that government should engage in more effective external communication to improve citizen trust and maintain political legitimacy. An important part of the belief is that more effective communication can lead to more favorable media coverage that ultimately shapes citizen trust in government. However, the link between government communication and media coverage remains empirically untested. Through a survey of 881 government and business communicators, this study tests the relationship between external communication activities and media coverage. The study shows that government organizations report being less likely to have favorable news coverage than their private counterparts, but most government organizations do report that their media coverage is favorable. Moreover, the results show that active media interaction, organizational support for communication, and adequate communication budget are associated with reporting more favorable coverage. In comparison, a different set of variables, except adequate communication budget, are found to affect whether business organizations report having more favorable media coverage.

Government communication is pervasive and has an impact on every aspect of American public life. However, there is minimal theory-driven research in this critical area of communication. This research explores comparisons of communication practices and the status of professional development among the four levels of U.S. government organizations through a survey of 781 government communicators. The study identifies six significant differences and two similarities in how the public sector environment affects communication practices at the city, county, state, and federal levels. The findings were applied to a modification of the government communication decision wheel, a model that offers a theoretical foundation for the study of government communication within its unique environmental context free from the bias of corporate-centric research assumptions. The findings contribute to communication theory development for the underresearched public sector. Comparaisons des pratiques de communication du gouvernement americain : pour developper la roue des decisions communicationnelles du gouvernement J. Suzanne Horsley, Brooke Fisher Liu, & Abbey Blake Levenshus La communication gouvernementale est omnipresente et affecte tous les aspects de la vie publique americaine. Neanmoins, il existe tres peu de recherches guidees par la theorie dans ce domaine critique de la communication. Cette recherche explore des comparaisons dans les pratiques communicationnelles et le developpement professionnel aupres de quatre niveaux gouvernementaux americains, par une enquete menee aupres de 781 agents de communication du gouvernement. L’etude identifie cinq differences importantes et trois similarites dans les facons par lesquelles le milieu du secteur public influence les pratiques de communication aux niveaux de la municipalite, du comte, de l’Etat et du pays. Les resultats ont ete appliques de facon a modifier la roue des decisions communicationnelles du gouvernement, un fondement theorique pour l’etude de la communication gouvernementale dans son milieu unique, sans les biais des hypotheses de recherche axees sur le secteur prive. Les resultats contribuent au developpement des theories en communication a propos du secteur public, toujours sous-etudie. Vergleiche von Kommunikationspraktiken der US-Regierung: Eine Erweiterung des Kommunikationsentscheidungsrads der Regierung J. Suzanne Horsley, Brooke Fisher Liu, & Abbey Blake Levenshus Die Kommunikation der Regierung ist allgegenwartig und beruhrt jeden Aspekt des Lebens der amerikanischen Offentlichkeit. Dennoch gibt es wenig theoriebasierte Forschung in diesem zentralen Feld der Kommunikation. Diese Studie betrachtet Vergleiche der Kommunikationspraktiken und professionellen Entwicklung auf vier Ebenen der US-Regierung mittels einer Umfrage unter 781 Regierungskommunikatoren. Die Studie identifiziert funf signifikante Unterschiede und drei ahnliche Aspekte, wie der offentliche Sektor die Kommunikationspraktiken auf Stadt-, Landkreis-, Lander- und Bundesebene beeinflusst. Die Ergebnisse wurden zur Modifikation des Kommunikationsentscheidungsrads der Regierung herangezogen - eine theoretische Basis fur die Untersuchung von Regierungskommunikation innerhalb ihres einzigartigen Kontextes und frei von Befangenheiten unternehmenszentristischer Forschungsannahmen. Die Ergebnisse tragen zur Entwicklung von Kommunikationstheorie im bislang unterbeleuchteten offentlichen Sektor bei. Las Comparaciones de las Practicas de Comunicacion del Gobierno de los EE.UU.: Expandiendo la Comunicacion de la Rueda de Decision del Gobierno J. Suzanne Horsley, Brooke Fisher Liu, & Abbey Blake Levenshus Advertising and Public Relations, University of Alabama, 255 S Central Campus Dr., Room 2400, Salt Lake City, UT 84112, USA Resumen La comunicacion del gobierno es dominante y toca cada aspecto de la vida publica Americana. No obstante, hay un minimo de investigacion dirigida por la teoria sobre esta area de comunicacion critica. Esta investigacion explora las comparaciones de las practicas de comunicacion y el desarrollo profesional entre 4 niveles del gobierno de los EE.UU. mediante una encuesta de 781 comunicadores del gobierno. Este estudio identifica 5 diferencias significativas y 3 similitudes en como el sector publico del medio ambiente afecta las practicas de comunicacion al nivel de la ciudad, el condado, el estado y el estado federal. Estos hallazgos fueron aplicados a modificacion de la comunicacion de la rueda de decision del gobierno, una fundacion teorica para el estudio de la comunicacion del gobierno dentro de este contexto unico del medio ambiente libre de las preconcepciones de las asunciones de la investigacion centradas en las corporaciones. Los hallazgos contribuyen al desarrollo de la teoria de la comunicacion para el sector publico poco investigado.

This study investigates the differences and similarities in communication practices between the public and private sectors. Through a survey of 976 government and corporate communicators, 12 organizational attributes previously identified in research on the government communication decision wheel (Liu & Horsley, 2007; Liu & Levenshus, 2008) were tested. The results indicated differences between the two groups in budgets, political influence, communication frequency, public pressure, interaction with other organizations, media coverage frequency, media coverage evaluation, and impact of legal frameworks as they relate to communication practices. No significant differences in diversity of publics, opportunities for professional development, participation in organizational leadership, or management support for communication between the two groups were found. The findings allowed for refinement of this developing model of government communication.

PurposeThis paper seeks to map the employment of female professionals to create a collective biography of women in US public relations from 1940‐1970. It aims to suggest that women were active leaders in many areas of public relations, despite the exclusion of women from most historical accounts.Design/methodology/approachThe author completed a content analysis of a women's professional directory published in 1970. This directory summarizes women's accomplishments during this critical time period in the development of the public relations profession. The sample of 520 entries was analyzed for demographics and career statistics in relation to social perceptions that prevailed during this timeframe.FindingsThe paper offers empirical insights into the work of female public relations practitioners. It quantifies employment in managerial and technical positions in a variety of industries, charts the trends in employment, and offers support for theoretical explanations for why women were essentially invisible in public relations publications and historical records.Research limitations/implicationsThe findings from this research are limited in that they are based on a directory full of self‐reported success stories. Therefore, additional research is needed before these results can be generalized to the population under study.Originality/valueThis paper creates a collective biography of women in public relations that complements the research that has been done on a few individual women. This research contributes to a more robust explanation of the development of US public relations.

We argue that the existing public relations and communication models do not adequately account for the unique environmental characteristics of the public sector. By reviewing the public sector environment literature, we identify 8 attributes that affect government public relations: politics, focus on serving the public, legal constraints, extreme media and public scrutiny, lack of managerial support for public relations practitioners, poor public perception of government communication, lagging professional development, and federalism. We then review 5 existing public relations models, arguing that none of these models fully incorporates the unique environmental characteristics of the public sector. We conclude by proposing a new model: the government communication decision wheel.

This article explores approaches to crisis communication and the application of those approaches by organizations responding to a disaster. The authors conducted a survey of 107 state government agencies to learn about government efforts in situations requiring crisis communication. Generally, the survey results suggest that although state agencies enjoy a positive relationship with the media, they have little proactive communication with the media, and less than half have a written crisis communication plan. Significant associations were found between the variables under study, including size of the organization, roles in crisis situations, media relationships, and preparation of a crisis communication plan. Case studies and additional evaluations of communication resources are needed to help determine the ability of the public sector to respond effectively to crises. This article considers the needs of state agencies and proposes a conceptual approach that synthesizes a crisis communication process designed for the public sector.

Wound complication rates after mastectomy are associated with several factors, but little information is available correlating biopsy technique with the development of postmastectomy wound complications. Fine-needle aspiration (FNA) biopsy is an accurate method to establish a diagnosis, but it is unknown whether this approach has an impact on complications after mastectomy.Charts of 283 patients undergoing 289 mastectomies were reviewed to investigate any association between biopsy technique and postmastectomy complications.The diagnosis of breast cancer was made by FNA biopsy in 50%, open biopsy in 49.7%, and core needle biopsy in 0.3%. The overall wound infection rate was 5.3% (14 of 266), but only 1.6% when FNA biopsy was used compared with 6.9% with open biopsy (p = 0.06). Among 43 patients undergoing breast reconstruction concomitantly with mastectomy, the infection rate was 7.1% (0% after FNA, 12% after open biopsy). Neither the development of a postoperative seroma (9.8%) nor skin flap necrosis (5.6%) was influenced by the biopsy technique used.These data suggest that wound infections after mastectomy may be reduced when the diagnosis of breast cancer is established by FNA biopsy.

Molecular graphics screening of potential zeolite catalysts for the selective synthesis of 2,6-diisopropylnaphthalene indicated that mordenite was a promising candidate. Molecular mechanics calculations of the minimum energy pathway for diffusion of the diisopropylnaphthalene isomers in mordenite showed that significant energy barriers exist for the 2,7 isomer, while the diffusion of the 2,6 isomer is unimpeded. In the case of zeolite L, no significant energy barrier was found for either isomer. In an experimental study of naphthalene isopropylation in a batch autoclave reactor, mordenite produced a 2,6/2,7 ratio of 2.5, while zeolite L was essentially nonselective. The combination of molecular graphics and molecular mechanics appears to be a powerful and reliable method for the screening of zeolites for selective catalysis.

The following autobiography is both authentic and true. I have had many opportunities of testing its truth in various ways during a friendship of some eighteen months, during which the writer has been pursuing the less exciting and less lucrative occupation of a teetotal costermonger....

OBJECTIVE: This study was done to determine the long-term outcome of breast conservation therapy (BCT) for patients with early-stage breast cancer during a period of treatment evolution at a single institution. SUMMARY BACKGROUND DATA: Breast cancer treatment has evolved from extensive surgical extirpation of the breast to treatment options that conserve the breast. Prospective and retrospective studies have confirmed the efficacy of BCT and justify its use for many patients with early breast cancer, but there is no universally accepted consensus as to who benefits from more aggressive application of surgery or radiotherapy in BCT. Prognostic variables for breast cancer and information on factors that contribute to local recurrence help predict BCT results. Continued analysis of BCT still is necessary to improve patient outcome. METHODS: Eighty-five patients treated with BCT (lumpectomy with adjuvant radiation therapy) at the Medical College of Virginia from 1980 to 1990 were identified. Clinicopathologic parameters and treatment details were analyzed for relationship to development of local recurrence, distant metastasis, and survival. Fisher's exact test was used for comparisons. Actuarial survival curves were plotted. The earlier treatment period (1980-1985) was compared with the later treatment period (1985-1990). RESULTS: Median follow-up was 5 years. Actuarial overall survival was 83% at 5 years (69% at 10 years), and 5-year distant metastasis-free survival was 79%. The 5-year actuarial local recurrence rate was 6.6% (crude rate 10.6%, 9/85). Young patients (age < 40 years) were found to be at increased risk for local recurrence (24% < 40 years vs. 6% > or = 40 years, p < 0.05). Tumor margins < or = 3 mm were more frequently found, and lumpectomy site radiation boost was used increasingly from 1986 to 1990. Almost half of all local recurrences occurred after 5 years. CONCLUSIONS: Survival and local recurrence rates were comparable to other series. Young patients were found to be at increased risk for local recurrence. Negative microscopic margins, even when close, can provide low local recurrence rates when adjuvant radiation therapy is administered.

Potential zeolite catalysts for the selective synthesis of 2,6-diisopropylnaphthalene have been screened using molecular graphics and molecular mechanics. The screening indicated that mordenite should be selective and zeolite L nonselective, in agreement with experiment.

A random sample of subjects over 65 years of age who had replied to a postal questionnaire on respiratory symptoms was asked to attend for lung function studies and, if fit, an inhaled methacholine bronchial challenge. Of 283 subjects, 180 (63.6%) agreed to attend. Most (98%) subjects performed reproducible spirometry, with no evidence of fatigue on repeated testing. However, 20 subjects were found to be unsuitable for challenge (forced expiratory volume in 1 s, (FEV1)1 litre or unable to perform spirometry reproducibly). The dose of methacholine producing a 20% fall in FEV1 was termed the PD20. A positive challenge with PD206.13 mumol methacholine was found in 69 of 160 (43%) subjects studied, with highly reactive airways (PD201.0 mumol methacholine) in 19 of 160 (12%). Bronchial hyperreactivity, which is closely associated with clinical asthma, was found to be far more common amongst the elderly than previously recognised. Low initial FEV1 (1-1.5 litres) predisposed to both a positive challenge (p0.01) and also to highly reactive airways (p0.01), generally associated with respiratory symptoms. Subjects with low (1-1.5 litres) baseline FEV1 were five times more likely to have highly reactive airways than those with FEV11.5 litres, confirming a relationship between baseline airway calibre and bronchial reactivity. Early detection of subjects with low FEV1, who are therefore more likely to have increased airway reactivity, may help to reduce respiratory morbidity in the elderly with considerable benefit both to patients and to the Health Service.

This contribution demonstrates the usefulness of molecular graphics, molecular mechanics, and molecular dynamics in the study of the structural, thermodynamic, and transport properties of different sorbates within various molecular sieves. Five significant applications to zeolite chemistry are reviewed.

Fifty consecutive patients who underwent 52 formal hepatic resections (excluding isolated wedge resections) for metastatic colorectal cancer were analyzed to determine whether DNA content was of prognostic significance. The Dukes' stages of the colorectal primaries were: A (10%), B (20%), C (40%), D (28%), and unknown in 2%. Four patients whose liver metastases were discovered at the time of resection of the primary bowel cancer underwent concomitant liver resection, and the remaining patients underwent delayed resections. The hepatic resections performed were right lobectomy (50%), extended right lobectomy (19%), left lobectomy (13%), left lateral segmentectomy (6%), left lobectomy and right wedge (6%), extended left lobectomy (4%), and right lobectomy and left wedge (2%). The overall morbidity rate was 29%. The in-hospital mortality rate was 9%. As of November 1991, 36 patients have recurred. The 5-year actuarial survival was 28%. Flow cytometry could be performed on 37 archival specimens, 15 of which were found to be diploid whereas 22 were aneuploid. All metastases from Dukes A colorectal primaries demonstrated a diploid DNA content. In addition, there was no difference in actuarial survival between diploid and aneuploid tumors. These data suggest that in selected patients, formal hepatic resection of colorectal liver metastases can be performed with an acceptable morbidity rate, mortality rate, and survival, but ploidy of the resected tumor is not of prognostic significance.

This study was carried out to estimate the prevalence of respiratory symptoms among people aged 65 years and older and assess the value of a postal survey in obtaining this information. A questionnaire was sent to 2011 subjects (957 men) drawn by age-stratified random sampling from the age-sex registers of four New Forest group practices (1:3.3 sample). A total of 1803 replied, a 96.2% response after excluding 136 who had died or moved from the area. The accuracy of replies was verified for 355 (20%) randomly selected subjects. Forty per cent had no respiratory symptoms. Exertional breathlessness was common (38%), increasing in prevalence with age but not with smoking history, and was the only symptom reported by 10% of subjects. Only 14.2% were current smokers; more of the subjects aged 85 years and over were lifelong non-smokers. Two hundred and ninety-six (16.4%) had chronic bronchitis, which was more common among smokers; 151 (8.4%) gave a history of asthma, of whom half (76) had active asthma, which was slightly less common among the very elderly subjects. Only 489 (27.1%) of subjects had seen their doctors with chest symptoms during the preceding 2 years.

• New rules for quality assurance provoked a comparison of effects of two approaches used concurrently for 14 years. In an incidental approach, a multidisciplinary conference reviewed all postoperative complications as they occurred and attributed each to one of six causes. Remedies were instituted and data were filed. In a statistical approach, death and complication rates were computed annually and compared with previous years' rates and with rates reported to Congress as national norms. Statistics suggested acceptable quality in each specialty but calculations were tedious and differences achieved significance too rarely or too slowly to identify problems, protect patients, and improve care. The incidental approach was popular and produced immediate improvements in patient care. Conferees attributed one half of complications to errors. Frequent acknowledgment of susceptibility to error may contribute to the safety and quality shown by our statistics. ( Arch Surg . 1992;127:733-738)

Relativistic Xα–scattered‐wave molecular orbital calculations have been carried out on the uranyl ion UO22+. The calculated orbital eigenvalues are in good agreement with the results of a recent x‐ray photoelectron spectroscopy study of uranyl compounds. An interpretation of the optical spectrum of the uranyl ion in terms of a Hund’s case (c) (ω, ω) coupling scheme is given.

The ionization potentials corresponding to the formation of the lowest‐lying states of doubly ionized ammonia have been measured by double charge transfer spectroscopy, the translational energy analysis of H− ions arising from double charge transfer between 4 keV protons and NH3. SCF–CI calculations have been carried out for the lowest lying states of NH3++ at the equilibrium geometry of the neutral molecule. The assignment of the experimental energy values to given states of NH3++ is discussed. Fairly good agreement between experimental and calculated double ionization potentials is obtained.

The electron energy loss spectra of gaseous thiophene and thiolane in the regions of S 2p, S 2s, and C 1s are presented along with the x‐ray photoelectron yield (NEXAFS) spectra of both gases in the region of S 1s excitation. The thiophene spectra are compared to the corresponding NEXAFS spectra of solid (multilayer) and monolayer thiophene on Pt (111). MS‐Xα calculations of the C 1s, S 2p, and S 1s excitation spectra of free thiophene are also reported. Intercomparison of the gas, surface, and calculated spectra allows a complete interpretation of the spectral features and facilitates determination of the molecular orientation of thiophene with respect to the surface in both the compressed [thiophene on Pt (111) at 150 K] and relaxed [thiophene on Pt (111) at 180 K] monolayer phases.

K shell excitation spectra of the aromatic molecules benzene and pyridine in the gas phase are compared to those for the solids (ices) and for monolayers chemisorbed on Pt(111). The gas phase and solid spectra are essentially identical and even the spectra for the chemisorbed molecules exhibit the same resonances. Because of the orientation of the molecules upon chemisorption the latter spectra show a strong polarization dependence as a function of x‐ray incidence. This polarization dependence in conjunction with a multiple scattering Xα calculation for the benzene molecule allows us to assign the origin of all K shell resonances. The resonances are found to arise from transitions to π* antibonding orbitals and to σ* shape resonances in the continuum. The shape resonances are characterized by potential barriers in high (l=5 and 6) angular momentum states of the excited photoelectron. The polarization dependence and energy position of the resonances allow the molecular orientation on the surface to be determined and show that the change in the carbon–carbon bond length is less than 0.02 A.

The carbon K‐shell excitation spectra of gaseous cyclic hydrocarbons, both saturated (cyclopropane, cyclobutane, cyclopentane, cyclohexane) and unsaturated (cyclopentene, cyclohexene, and cyclooctatetraene), have been recorded by electron energy loss spectroscopy under dipole‐dominated conditions. These are compared to the NEXAFS spectra of multilayers and monolayers of C4H8, C5H8, C6H12, and C8H8 on Pt(111). Multiple scattering Xα calculations of the spectra of cyclopropane, cyclobutane, and cyclohexane are also reported. In most cases the gas and solid spectra are essentially the same indicating that intramolecular transitions dominate in the condensed phase. The NEXAFS polarization dependence of the condensed phases has assisted spectral assignments and the determination of the molecular orientation in the monolayer phase. In the saturated species a sharp feature about 3 eV below the carbon 1s ionization threshold is identified as a transition to a state of mixed Rydberg/valence character with the π*(C...

Near-edge X-ray absorption fine structure (NEXAFS) spectra have been measured for ethylene chemisorbed on Pt(111) at 90 and 300 K. From the polarization dependence of the spectra at 90 K, ethylene is found to lie down with a π bond to the surface. The spectra collected at 300 K indicate a CC bond normal to the surface in ethylidyne, and a SCF Xα calculation was carried out to assign the K-edge transitions in this species. The ethylidyne carboncarbon bond (which is nominally a single bond) appears to be shorter (≈0.03 A) than that for chemisorbed ethylene.

The role of thermal energy in the laser‐induced unimolecular decomposition of a complex molecule, UO2 (hfacac)2⋅THF, has been investigated experimentally and theoretically. In the temperature range 70–150 °C, the laser‐induced decomposition yield was observed to vary exponentially with the initial temperature of the molecules at low yields, changing to a linear variation at high yields. The laser‐induced decomposition process has been represented by a model that simulates the pumping of an ensemble of molecules, initially spread over a broad Boltzmann distribution, through a series of dissociative levels. This model is able to reproduce the experimental observations assuming a ’’loose’’ transition state that leads to a value for the A factor in the range 1016–1018 sec−1.

The relationship between the intensity of the L 2 and L 3 x‐ray absorption threshold resonances and d orbital occupancy has been investigated for a series of compounds of platinum and iridium and the pure metals, using Xα‐SW molecular orbital calculations to obtain the unoccupied d orbital states. The change in d orbital occupancy caused by formation of the core hole was found to be fairly constant in different compounds and the pure metal. The difference between the d orbital occupancy in platinum metal and the d orbital occupancy in a given platinum compound agrees well with the calculated effective charge on the platinum atom in the compound. The areas of the threshold resonance lines were obtained by a deconvolution of the absorption edge into a Lorentzian component and an underlying ’’step’’ representing the onset of absorption to continuum states. For a series of platinum compounds, a linear relationship was obtained between the unoccupied d orbital states calculated in the core hole potential, and the sum of the areas of the L 2 and L 3 threshold resonance lines (corrected for the different degeneracies of the initial state). However, this relationship could not be applied to IrO2 because of the absence of transitions to empty d states at the top of the valence band.

Molecular beam mass spectrometric, laser-induced fluorescence, and IR-IR double resonance measurements have been applied to the investigation of the IR laser chemistry of bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)dioxouranium(VI) trimethylphosphate (UO/sub 2/(hfacac)/sub 2/TMP). The results have been correlated with energy deposition and FT IR absorption data, yielding a more complete understanding of the dissociation mechanism than obtained in previous studies of an analogous molecule, UO/sub 2/(hfacac)/sub 2/THF. IR dissociation appears to be slower, and more complicated, than previously deduced. Disappearance of laser-induced fluorescence or parent molecular ion upon CO/sub 2/ laser irradiation is attributable to rapid isomerization (> 10/sup 7/s/sup -1/) of parent molecules to a species with a red-shifted uranyl absorption feature. The latter molecules have sufficient excitation to subsequently decompose by loss of TMP. For the TMP complex, formation of the isomer requires ..delta..H approx. 10 kcal/mol and ..delta..S approx. 20 eu, which is consistent with ring opening (via U-O bond) of the bidentate hfacac ligand, compared to ..delta..H approx. = 36 kcal/mol and ..delta..S = 55 eu for dissociation of TMP. For excitation of either uranyl or TMP vibrational modes with 450-ns fwhm CO/sub 2/ laser pulses, the dissociation yield depends only on the energy deposited and the decomposition rate is consistentmore » with RRK predictions.« less

This paper summarizes the results of research in a number of different areas of the laser chemistry of UF 6 . These include: IR excitation and unimolecular dissociation; two color IR excitation; atom-molecule reactions; and UV photodissociation and photochemistry.

The near edge x‐ray absorption fine structure (NEXAFS) spectra of ethylene on Pt(111) at 90 and 300 K have been measured and compared to the spectra calculated using the multiple scattering Xα method for cluster models of adsorbed ethylene and ethylidyne. The results indicate that ethylene is adsorbed in the di‐σ configuration (sp3 hybridization) at 90 K, and that the π* orbital retains its identity in this configuration, with no component along the C–C axis. The spectrum obtained at 300 K is attributed to ethylidyne (CCH3) and the calculated spectrum for a cluster consisting of this species bonded symmetrically to three Pt atoms is in good agreement with experiment. The calculations show that the multiple scattering molecular cluster approach is a useful technique for interpreting the NEXAFS spectra of adsorbed molecules.

Four hundred patients with resectable colon and rectal cancers were operated on by 37 surgeons at 31 institutions. Patients were monitored with carcinoembryonic antigen (CEA) level determinations and clinical examinations. One hundred thirty patients had recurrences, and 75 were reoperated on, with 43 reoperations CEA-directed and 32 clinically directed. Two of 75 died within 1 month after the second operation. Twenty-two second-look patients remain free of disease 5 years after their second operaton. The highest resectability of recurrent cancer occurred in patients with a CEA level below 11 ng/ml in whom the CEA level was determined at intervals of 1 to 2 months. Cancer 55:1284-1290, 1985.

Measurement of the isotopic selectivity as a function of temperature are described for IR laser induced dissociation of UO2(hfacac)2⋅THF in a low density molecular beam. The measured selectivity was found to increase from 1.2 at 120 °C to 1.9 at 65 °C. This behavior is consistent with a model which takes into account both the initial thermal energy content of the molecule and the energy barrier to dissociation. Indeed, such behavior is expected for any complex molecule which has isotopically shifted, but overlapping absorption spectra as is the case for the 235U and 238U containing molecules used in this study.

The temperature dependence of the CO2 laser‐induced decomposition spectral linewidths and yields for jet‐cooled UO2(hfaa)2 TMP and UO2(hfaa)2 THF molecules has been studied using laser‐induced fluorescence detection and photoionization time‐of‐flight mass spectrometry on a pulsed supersonic beam of uranyl molecules seeded into a helium carrier gas. The two uranyl species, although chemically very similar, show a remarkable difference in the temperature dependence of the linewidth. For UO2(hfaa)2 TMP, the linewidth decreases upon cooling by a factor of ∼15, while the UO2(hfaa)2 THF linewidth decreases by only a factor of ∼2.6 over the same temperature range. The differences in the linewidth behavior are reflected in the yield curves for the laser‐induced reaction for the cooled molecules. These results for UO2(hfaa)2 TMP, to our knowledge, represent the first measurements of the temperature dependence of a T2 line broadening process for an isolated gas phase molecule. Detection of beam molecules as well as molecular decomposition fragments by multiphoton ionization is found to be ∼103 times more efficient than detection by resonant two‐color photoionization.