Total fragmentation of H 2 O and D 2 O has been studied as a function of incident energy over the range from threshold to 325 eV. A small subset of possible dissociation channels has been selected by making use of a novel solid xenon matrix detector which is selectively sensitive to O( 1 S) metastable atoms. O-fragment kinetic energies and appearance potentials have been measured and significant isotopic effects are observed. Within the errors of the measurements the cross section for O( 1 S) production from H 2 O is the same as that from D 2 O. The cross sections reach a maximum value of 1.5 × 10 −18 cm 2 at 100 eV incident electron energy.
Making use of a novel solid xenon matrix detector which is selectively sensitive to O͑ 1 S 0 ͒ metastable atoms, a new dissociation channel, via a 1 A 1 repulsive state, has been uniquely identified following electron impact on D 2 O molecules. Careful measurements of the O fragment kinetic energies and appearance potentials have allowed partial reconstruction of the potential energy surface involved. The excitation function for production of O͑ 1 S 0 ͒ has a shape which is characteristic of an optically allowed transition in the parent molecule and has a maximum value of 1.2 3 10 218 cm 2 at 100 eV incident electron energy. [S0031-9007(97)
Solid Xe was used to detect oxygen atoms in the 1S metastable state following their production by electron impact on nitric oxide. Time‐of‐flight spectra of O(1S) for several electron impact energies were obtained. The repulsive portion of the potential curve for one of the parent states of NO which led to O(1S) was deduced from the data.
Epstein-Barr virus (EBV) associated lymphoproliferative disorders includes a diverse group of diagnoses, encompassing both B-cell and T-cell lineages. With EBV mucocutaneous ulcers becoming a World health Organization diagnosis in 2018, introduction of the disease entity will be beneficial to the practicing otolaryngologist. We are reporting a case of a 69-year-old male with history of rheumatoid arthritis on methotrexate, recently undergoing dental extractions, who then developed multiple oral ulcerations and bony erosions of his palate and alveolar ridge. Associated symptoms included a large 3.0 cm neck mass, splenomegaly, and pulmonary nodules. Histopathology showed EBV+ lymphomatoid granulomatosis. Upon removal of immunosuppressive agent, patient’s symptoms improved with resolution of oral lesions, as well as systemic symptoms.
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