Cyclopropane adiabatic frequencies

Adiabatic frequencies of cyclopropane are compared in Table 2 with those of some other hydrocarbons [28]. The adiabatic CC frequency is about 40 and the adiabatic CH stretching frequency about 130 cm i larger than the corresponding values for cyclohexane. Compared to ethene, the adiabatic CH stretching frequencies are almost identical, which is in line with the high dissociation energy of the CH bond of cyclopropane [29]. The same observation has been made... 

TABLE 20. Adiabatic internal frequencies of cyclopropane and some simple hydrocarbons from Reference 163 ... 

A characterization of vibrational normal modes in terms of adiabatic internal modes is straightforward with the definitions given in the previous sections. As an example, the vibrational modes of cyclopropane [28] will be discussed. They have been calculated at the FIF/6-31G(d,p) level of theory and they are compared with experimental frequencies in Table 1. 

All frequencies in cm l. Scaled HF/6-31G(d,p) and MP2/(9s5pld/4slp)[4s2pld/2slp] frequencies scaling factors are 0.87 (HF) and 0.95 (MP2), respectively. Each normal mode is dissected into adiabatic internal vibrations [28]. The notation CH (6 x 16%) implies that all six CH stretching modes (each with 16%) of cyclopropane contribute to the normal mode 1. 

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See also in sourсe #XX -- [ ]

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