 上传我的文档
 下载
 收藏
主要从事画册，展板设计工作，熟练PHOTOSHOP、CAD等常用软件。勤恳好学，踏实肯干。
 下载此文档
正在努力加载中...
Study of uranyl formate thermolysis
下载积分：1825
内容提示：Study of uranyl formate thermolysis
文档格式：PDF|
浏览次数：0|
上传日期： 05:44:43|
文档星级：
该用户还上传了这些文档
Study of uranyl formate thermolysis
官方公共微信114网址导航Spectroscopy and Photochemistry in Single Crystals of Uranyl Formate Monohydrate
Title:Spectroscopy and Photochemistry in Single Crystals of Uranyl Formate Monohydrate.
Affiliation:AA(PRINCETON UNIVERSITY.)
Publication:Thesis (PH.D.)--PRINCETON UNIVERSITY, 1982.Source: Dissertation Abstracts International,
Volume: 43-01, Section: B, page: 0173.
Publication Date:03/1982
Category:Physics: Condensed Matter
Bibliographic Code:
UO(,2)CH(OO)(,2)(.)H(,2)O, (UFM) is an orthorhombic crystal (Fdd2,
C(,2v)('19)) with two uranyls per unit cell. Above 210(DEGREES)K, when
uranyl is excited by visible light, a two-step reaction occurs. The
primary photochemical step is. U(VI)O(,2)('++) + HCOO('-) (---&) U(V)
+ (HCOO(.) or CO(,2)('-)). (1). A study of UFM in the oriented solid
explores one of the most basic chemical reactions--the redox reaction.
High resolution, polarized absorption and excitation specta were taken
on single crystals at liquid helium temperatures. Eight electronic
origins are identified, each split into doublets by factor group
interactions. Uranyl (a)symmetric stretch vibronic progressions (do not)
preserve the factor group splittings and polarizations of their origins.
The spectrum of UFM lies closer to the (omega)-(omega) limit, as opposed
to Russell-Saunders, than Cs(,2)UO(,2)Cl(,4). Low site symmetry
depolarizes the B-symmetry components of the origins. Below 2(DEGREES)K,
where UFM exhibits non-single exponential luminescence decay, migration
to traps is limited. By 20(DEGREES)K, where the curves become single
exponential and drop tenfold in the value of the lifetime, emission is
occurring from UFM in thermal equilibrium with a population of killer
traps. Above 70(DEGREES)K, the lifetime slowly rises. It peaks at
135(DEGREES)K, and then drops steeply, falling below detectability by
210(DEGREES)K. The drop is accompanied by the onset of photoreactivity.
The rise in emission is attributed either to a decrease in trapping
efficiency or to a hindered migration to traps due to a thermal
population of bound (DELTA)(,g) excitons. ESR studies show that a signal
at g = 2.0 observed at 77(DEGREES)K is from surface radicals. Below
20(DEGREES)K, a signal near g = 2.1 is due to organic radicals in the
bulk generated by the photochemical step. Studies on a single crystal
resolve these signals into components that reflect the crystallographic
symmetry elements. A signal near g = 3.4 is attributed to the
g(,(PARLL)) component of U(V). The primary photoproduct may be a
U(V)-organic radical pair, coupled by hyperfine and spin-orbit
interactions. The pairs are at sites with nearly intrinsic symmetry.
They may be the traps responsible for the behavior of the luminescence.
A model for the primary photochemical reaction is discussed. The initial
step is a biexcitonic encounter between (pi)(,g) and bound-(DELTA)(,g)
excitons to form a uranyl doubly excited state that lies in the CT
region of the spectrum.
&&& (see )
Find Similar Abstracts:
Abstract Text
Query Results
Return &&&items starting with number
Query Form
arXiv e-printsuranyl ammonium nitrate
硝酸铀酰铵
核能专业术语(29) ...
uranyl ammonium fluoride 氟化铀酰铵
uranyl ammonium nitrate 硝酸铀酰铵
uranyl ammonium oxalate 草酸铀酰铵 ...
基于11个网页-
硝酸铀酰铵
&2,447,543篇论文数据，部分数据来源于
$firstVoiceSent
- 来自原声例句
请问您想要如何调整此模块？
感谢您的反馈，我们会尽快进行适当修改！
请问您想要如何调整此模块？
感谢您的反馈，我们会尽快进行适当修改！}