Ballistic energy

Schwarzer D, Kutne P, Schroder C, Troe J (2004) Intramolecular vibrational energy redistribution in bridged azulene-anthracene compounds ballistic energy transport through molecular chains. J Chem Phys 121 1754... 

We employ the above formalism and study the conductance of alkane chains of variable length (1-30 units). We have numerically verified that heat conduction in these systems is dominated by harmonic interactions [18]. A recent experiment confirmed this observation, demonstrating ballistic energy transfer in short hydrocarbon mono-layers [24]. 

Klunsch (Ref 72) has incorporated hydra-zinium nitroformate and aluminum hydride in plastisol NC formulations which cure at room temp without undesirable gas formation. A number of such formulations and calculated ballistic results are given in Table 21. Although these are attractive propint s from the standpoint of potential energy, their impact sensitivity was not described. Similar plastisol binder propellants in Table 18 were sensitive enough to impact to warrant extreme caution in processing into rockets. 

The ballistic mortar and lead block tests use only small amounts of explosive and are not applicable to slurry explosives which are too insensitive to detonate properly under such conditions. For these explosives it is useful to fire larger amounts of several kg under water and measure the period of oscillation of the gas bubble produced. The longer the period the greater the energy of the gas bubble and this part of the total energy of the explosive has been found to correlate well with the blasting effect of the explosive. 

Apart from fundamental constants and the liquid temperature, the variable parameters in the effective mobility equation are the quasi-free mobility, the trap density, and the binding energy in the trap. Figure 10.2, shows the variation of prff with e0 at T = 300 K for /tqf = 100 cm3v 1s 1 and nt = 1019cm-3. It is clear that the importance of the ballistic mobility (jl)l increases with the binding... 

In comparing the results of the quasi-ballistic model with experiment, generally pq[ = 100 cn v s-1 has been used (Mozumder, 1995a) except in a case such as isooctane (Itoh et al, 1989) where a lower Hall mobility has been determined when that value is used for the quasi-free mobility. There is no obvious reason that the quasi-free mobility should be the same in all liquids, and in fact values in the range 30-400 cmV -1 have been indicated (Berlin et al, 1978). However, in the indicated range, the computed mobility depends sensitively on the trap density and the binding energy, and not so much on the quasi-free mobility if the effective mobility is less than 10 crr v s-1. A partial theoretical justification of 100 cm2 v 1s 1 for the quasi-free mobility has been advanced by Davis and Brown (1975). Experimentally, it is the measured mobility in TMS, which is considered to be trap-free (vide supra). 

Table 10.4 lists the values of trap density and binding energy obtained in the quasi-ballistic model for different hydrocarbon liquids by matching the calculated mobility with experimental determination at one temperature. The experimental data have been taken from Allen (1976) and Tabata et ah, (1991). In all cases, the computed activation energy slightly exceeds the experimental value, and typically for n-hexane, 0/Eac = 0.89. Some other details of calculation will be found in Mozumder (1995a). It is noteworthy that in low-mobility liquids ballistic motion predominates. Its effect on the mobility in n-hexane is 1.74 times greater than that of diffusive trap-controlled motion. As yet, there has been no calculation of the field dependence of electron mobility in the quasi-ballistic model. 

TABLE 10.4 Electron Mobility, Trap Density, Binding Energy, and Activation Energy in the Quasi-ballistic Model... 

FIGURE 10.5 Standard free energy change, in various liquid hydrocarbons, versus temperature upon electron trapping from the quasi-free state according to the quasi-ballistic model. Reproduced from Mozumder, (1996), with the permission of Am. Chem. Soc. ... 

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