Alkanes, ionization spectra

These calculations have been conducted on the basis of RHF optimized geometries, considering the 6-31G basis set for the n-alkane compounds (11), and the 6-31G basis set for the polyacene series (12). In both cases, the basis set contention has been checked by comparison with more thorough investigations on small compounds, such as ADC[3] calculations (11a) on n-butane based on the 6-31IG, 6-31G and 6-31G basis, or the MRSDCI ionization spectrum of ethylene as obtained by Murray and Davidson (33) using a 196-CGTO basis set. 

FIMS Fingerprint. Field ionization mass spectrometry of a mixture affords a spectrum of the molecular ions since fragmentation is minimal. Thus a distribution of molecular sizes and hydrocarbon classes can be obtained from a single analysis. This is illustrated in Figure 1 which compares the FIMS fingerprints for JP-5 from Shale-I and Shale-II refining. Distinct differences can be noted. The preponderance of alkanes (C... 

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