Trapping multiple

In the case of a single level trapping state, Ei is the difference between the energy of the trap and the transport band edge, and a — where iVc,v, is the density 

---

Multiple cryogenic traps between the pre-column and the analytical column were developed in 1993 by Ragunathan et al. (23). These authors found that a multiple trap configuration provided the necessary resolution and automated sampling for simultaneous GC/IR and GC/MS determination of very complex mixtures. A... 

Concerning the nature of electronic traps for this class of ladder polymers, we would like to recall the experimental facts. On comparing the results of LPPP to those of poly(para-phenylene vinylene) (PPV) [38] it must be noted that the appearance of the maximum current at 167 K, for heating rates between 0.06 K/s and 0.25 K/s, can be attributed to monomolecular kinetics with non-retrapping traps [26]. In PPV the density of trap states is evaluated on the basis of a multiple trapping model [38], leading to a trap density which is comparable to the density of monomer units and very low mobilities of 10-8 cm2 V-1 s l. These values for PPV have to be compared to trap densities of 0.0002 and 0.00003 traps per monomer unit in the LPPP. As a consequence of the low trap densities, high mobility values of 0.1 cm2 V-1 s-1 for the LPPPs are obtained [39]. 

Equipment available (HPLC, automated PSU, SPE, flow probe, high-field spectrometer) will determine the overall LC-NMR sensitivity and levels of impurities that can be analysed. For low-level impurities the time required for multiple trapping on SPE cartridges may also need to be considered [84]. 

Traditionally, charge-carrier transport in pure and doped a-Se is considered within the framework of the multiple-trapping model [17], and the density-of-state distribution in this material was determined from the temperature dependence of the drift mobility and from xerographic residual measurements [18] and posttransient photocurrent analysis. 

The fraction rj/rja= d is thus the rescaling of the classical Kramers rate according to the parameters classifying the multiple trapping system with broadly distributed waiting times. Similarly, in the underdamped case, one finds the fractional Kramers rate... 

Let us define the (multiple) trapping events. As mentioned before, trapping describes the occasional immobilization of the random walking test particle... 

---