| 1. |
- Najeeb, P. K., 1986-, et al.
(författare)
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Stability and Cooling of the C72- Dianion
- 2023
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 131:11
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the stability of the smallest long-lived all carbon molecular dianion (C72-) in new time domains and with a single ion at a time using a cryogenic electrostatic ion-beam storage ring. We observe spontaneous electron emission from internally excited dianions on millisecond timescales and monitor the survival of single colder C72- molecules on much longer timescales. We find that their intrinsic lifetime exceeds several minutes - 6 orders of magnitude longer than established from earlier experiments on C72-. This is consistent with our calculations of vertical electron detachment energies predicting one inherently stable isomer and one isomer which is stable or effectively stable behind a large Coulomb barrier for C72-→C7-+e- separation.
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| 2. |
- Najeeb, P. K., 1986-, et al.
(författare)
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Stability and Cooling of the C2−7 Dianion
- 2023
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 131:11
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the stability of the smallest long-lived all carbon molecular dianion () in new time domains and with a single ion at a time using a cryogenic electrostatic ion-beam storage ring. We observe spontaneous electron emission from internally excited dianions on millisecond timescales and monitor the survival of single colder molecules on much longer timescales. We find that their intrinsic lifetime exceeds several minutes—6 orders of magnitude longer than established from earlier experiments on . This is consistent with our calculations of vertical electron detachment energies predicting one inherently stable isomer and one isomer which is stable or effectively stable behind a large Coulomb barrier for →+e− separation.
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| 3. |
- Anderson, Emma K., 1986-, et al.
(författare)
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Fragmentation of and electron detachment from hot copper and silver dimer anions : A comparison
- 2023
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 107:6
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Tidskriftsartikel (refereegranskat)abstract
- We measured the spontaneous decays of internally hot copper and silver dimer anions, and , stored in one of the two ion-beam storage rings of the Double Electrostatic Ion Ring Experiment (DESIREE) at Stockholm University. A coincidence detection technique was utilized enabling essentially background-free measurements of -> Cu + Cu- and -> Ag + Ag- fragmentation rates. Furthermore, the total rates of neutral decay products (monomers and dimers) were measured and the relative contributions of fragmentation and electron emission ( -> Cu2 + e- and -> Ag2 + e-) were deduced as functions of storage time. Fragmentation is completely dominant at early times. However, after about 20 ms of storage, electron emission is observed and becomes the leading decay path after 100 ms for both dimer anions. The branching ratios between fragmentation and electron emission (vibrationally assisted autodetachment processes) are very nearly the same for and Ag-2 throughout the present storage cycle of 10 seconds. This is surprising considering the difference between the electron affinities of the neutral dimers, Cu2 and Ag2, and the difference between the and the dissociation energies.
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| 4. |
- Franzén-Dahlin, Åsa, et al.
(författare)
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A randomized controlled trial evaluating the effect of a support and education programme for spouses of people affected by stroke
- 2008
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Ingår i: Clinical Rehabilitation. - : SAGE Publications. - 0269-2155 .- 1477-0873. ; 22:8, s. 722-30
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To determine whether a nurse-led support and education programme for spouses of patients affected by stroke improved the psychological health of the spouses.DESIGN: A longitudinal, open, randomized controlled trial.SAMPLE: One hundred spouses of stroke patients were randomly assigned to either an intervention or a control group.SETTING: The study was conducted in a hospital setting.INTERVENTION: The intervention consisted of six group meetings during six months, with a follow-up after further six months. Comparison between the intervention and the control groups was made at baseline, after six and 12 months using analysis with repeated measures.MAIN MEASURES: The Comprehensive Psychopathological Rating Scale--Self-Affective for psychological health.RESULTS: No significant difference was found between the intervention and control groups concerning overall psychological health. However, a subanalysis revealed that those who participated more frequently in the group meetings (five or six times) had significantly stronger psychological health (P<0.05). Knowledge about stroke increased over time in both groups, but participants in the intervention group learned more (P=0.041).CONCLUSION: Encouraging participation in the group meetings of a support programme might have a positive effect on psychological health.
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| 5. |
- Franzén-Dahlin, Åsa, et al.
(författare)
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Predictors of life situation among significant others of depressed or aphasic stroke patients
- 2008
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Ingår i: Journal of Clinical Nursing. - : Wiley. - 0962-1067 .- 1365-2702. ; 17:12, s. 1574-1580
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Tidskriftsartikel (refereegranskat)abstract
- AIM: The aim of this study was to examine predictors of the life situation of the significant other of depressed or aphasic stroke patients.BACKGROUND: Depression and aphasia are common consequences of stroke, and both may put pressure on the significant other who have to deal not only with a possible physical handicap but also with communication and/or serious psychiatric difficulties.DESIGN: Descriptive, cross-sectional study.METHODS: The participants were significant others of 71 depressed and 77 aphasic stroke patients. Depression was diagnosed according to the Diagnostic and Statistical Manual of Mental Disorder, and degree of aphasia was diagnosed with the Amsterdam Nijmegen Everyday Language Test. Assessments of the life situation, state of depression and aggression, personality change and need of assistance were made through questionnaires issued to the significant others.RESULTS: Perceived need of assistance was the only common predictor of life situation of the significant other in both groups (p < 0.001). With respect to the aphasic patients, perceived personality change (p < 0.001) and living with the patient (p = 0.004) were factors that had a negative effect on the life situation of the significant other.CONCLUSIONS: This study highlights that the perception of the patient's need of assistance is an important factor in predicting the life situation among spouses of depressed as well as aphasic stroke patients. A comparison of the two groups to explain the life situation of the significant others revealed greater explanatory power for the aphasic group.RELEVANCE TO CLINICAL PRACTICE: Assessments of the spouses' perception as well as of the patients' factual situation may identify those significant others at risk. With this new approach, necessary steps may be taken to alleviate pressure on the significant other.
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| 6. |
- Franzén-Dahlin, Åsa, et al.
(författare)
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Predictors of psychological health in spouses of persons affected by stroke
- 2007
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Ingår i: Journal of Clinical Nursing. - : Wiley. - 0962-1067 .- 1365-2702. ; 16:5, s. 885-891
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To identify predictors of psychological health and examine if these predictors change over time in spouses of stroke patients during the first year after stroke. A second aim was to identify gender differences in psychological health among the spouses.BACKGROUND: The impact of burden in long-term caregivers may result in psychological consequences for the spouse. The rehabilitation process for the patient can be negatively affected by a stressed caregiver and result in long-term hospitalization. To identify spouses at risk for physical and psychological distress is, therefore, essential to support those in need.DESIGN: Longitudinal, comparative study.METHODS: One hundred spouses of stroke patients were assessed at baseline, as well as after six and 12 months, regarding psychological health, well-being, own illness, need of assistance from general practitioner and/or district nurse, social network and knowledge about stroke. Stepwise multiple regression analyses were conducted for baseline, six- and 12-month assessments, respectively, with psychological health as the dependent variable.RESULTS: General well-being and presence of illness in spouse were the most prominent predictors of psychological health, throughout the first year.CONCLUSIONS: Enhancing psychological health and preventing medical problems in the caregiver are essential considerations to enable patients with stroke-related disabilities to continue to live at home.RELEVANCE TO CLINICAL PRACTICE: Evaluating the situation for spouses of stroke patients is an important component when planning for the future care of the patient.
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| 7. |
- Hedvall, Patrik, et al.
(författare)
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Treatment of asymptotic non-adiabatic couplings with higher order reprojection method in the diabatic representation
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The problem of asymptotic non-adiabatic couplings in heavy particle collisions is treated using the reprojection method. The mixing matrix that mix the asymptotic solutions of the coupled states to obtain appropriate boundary conditions, is here derived to second order yielding a faster convergence of the cross section. Additionally, the reprojection method is implemented in a diabatic representation and applied to inelastic scattering of Li+Na, H+H and to mutual neutralization in H++H- collisions.
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| 8. |
- Hörnquist, Johan, 1990-
(författare)
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A unified model of reactive scattering processes : Application to the H2 reaction complex
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, reactive scattering processes involving the H2 reaction complex are studied ab initio and fully quantum mechanically. These processes have in common that they involve highly excited electronic states, which could be either bound or resonant. Non-adiabatic couplings, which can be significant both at small and large internuclear distances, need to be included to account for the interaction between the bound electronic states. In addition, the electronic resonant states interact with the ionization continuum at small internuclear distances, which may cause the collision complex to autoionize. In this work, a model is developed which incorporates these different coupling mechanisms. By introducing a quasidiabatic model at small internuclear distances, resonant states and couplings to the ionization continuum are incorporated. The quasidiabatic model is combined with a strict diabatic description, which rigorously incorporates non-adiabatic couplings among the bound electronic states. Nuclear dynamics are solved for using a close-coupling approach in a strict diabatic representation, where a non-local complex potential is included to account for loss into the ionization continuum. With this model, various reactive scattering processes can systematically be studied using the same set of potential energy curves and couplings. The model is applied in studies of H++H- mutual neutralization, H(1s)+H(ns) and H++H- associative ionization as well as dissociative recombination and resonant ion-pair formation in electron collisions with HD+. Cross sections and branching ratios are compared with results from previous experiments and theoretical studies.
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| 9. |
- Hörnquist, Johan, et al.
(författare)
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Associative ionization in collisions of H plus + H- and H(1s) + H(ns)
- 2023
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 108:5
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Tidskriftsartikel (refereegranskat)abstract
- Associative ionization in collisions of H+ + H- as well as H(1s) + H(ns) with n = 2, 3, 4 is studied theoretically. Relevant adiabatic potential curves and nonadiabatic couplings are calculated ab initio and the autoionization from the lowest electronic resonant states in the 11+g/u and 31+g/u symmetries are considered. The cross sections are obtained by solving the coupled Schrodinger equation, including a complex potential matrix, in a strict diabatic representation. The importance of using a nonlocal description of autoionization is investigated. Associative ionization is also studied for different isotopes of hydrogen. Calculated cross sections are compared with results from measurements.
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| 10. |
- Hörnquist, Johan, 1990-, et al.
(författare)
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Dissociative recombination and resonant ion-pair formation in electron collisions with HD
- 2024
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 109:5
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a method for which a variety of reactive scattering processes involving the H2 reaction complex can be studied using the same set of potential curves and couplings. The method is based on a close coupling approach in a strict diabatic representation. By rigorously incorporating non-adiabatic couplings among bound states, we enable the computation of final state distributions. Loss into the ionization continuum is accounted for with a non-local complex potential matrix. The method has successfully been applied in the studies of H+ + H- mutual neutralization and H(1s) + H(ns) associative ionization. In this paper, we investigate the applicability of this method to dissociative recombination and resonant ion-pair formation in electron collisions with HD+. The importance of a non-local description of autoionization is demonstrated. Calculated cross sections and final state distributions are compared with results from experiments and previous theoretical studies.
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