Mode evolution through time

Cf (ti 2.73 y) has found several uses. It decays to 3.1% by spontaneous fission (the main decay mode is through a emission) leading to a neutron emission rate of 2.3 X10 n s kg (average n-energy 2.35 MeV). The n-dose rate is 22 kSv h kg Cf is the only nuclide that can provide a useful neutron intensity over a sufficiently long half-life to make it a useful neutron source. The low rates of heat emission (38.5 kW/kg), y-radiation (initially 1.3 x 10 photons s kg, yielding an initial dose rate of 1.6 kGy h kg y-ray intensity increases with time due to fission product build-up) and helium evolution (from a decay) allow fabrication of simple, small Cf sources that require no external power... 

The dynamics of the normal mode Hamiltonian is trivial, each stable mode evolves separately as a harmonic oscillator while the imstable mode evolves as a parabolic barrier. To find the time dependence of any function in the system phase space (q,pq) all one needs to do is rewrite the system phase space variables in terms of the normal modes and then average over the relevant thermal distribution. The continuum limit is introduced through use of the spectral density of the normal modes. The relationship between this microscopic view of the evolution... 

It is observed that the C-H out-of-plane deformation modes shift during isomerisation, as shown in Fig. 2. From the very long chain of cis-PA (Yc h = 735 cm ), p electrons become more and more localized within shorter chains, which are necessarily found at the end of the reaction (Yc-h = 743 cm- ). The case of trans-PA is opposite. The original short chains (Yc-h= 1013 cm"i) generate a long and highly delocalized system of p electrons (Yc-h = cm-i). Qualitatively, the isomerisation develops through three time domains (i) cis-PA 0-30, 30-130, 130-200 secs (ii) trans-PA 0-30, 30-60, 60-200 secs. The time evolution of the... 

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