Thermodynamic Parameters of the Target Species

2 Entropy, Heat Capacity and Hindered Rotation Contribution to Thermodynamic Parameters of the Target Species 

Contributions to and Cp g iT) from translation, scaled vibrations frequencies, and external 

Contribution toS°gg and Cp g T) from internal rotations (IR) are calculated by using the technique explained in chapter 2. Potential barriers for internal rotations about the C—C, C — OH, C—O, C—CH=0, Cd—C, Cd—Cd, Cd—O, Cd—OH, Cd—CH=0, Cb—C, Cb—Cd, Cb— O, Cb—CH=0 and 0—CH(=0) bonds in the stable molecules are determined at the B3LYP/6-31G(d,p) calculation level. A lower basis set, 6-31G(d,p) instead of 6-311G(d,p) is used, because the difference in accuracy between the two basis sets is negligible whereas the computation time difference is important. The same level was used for hindered rotation of radicals around RC —OH, C—C =0, RC —C=0, C—C(0 )=0, Cd—C R, RCd —CH=0, Cd—C =0, Cb—C =0 and RO—C (=0). Contributions for entropy and heat capacity from the internal rotors are estimated using these potentials. 

The total entropy and heat capacities (TVR + IR) are given in Table D1 and D2 of Appendix D. These values are used to determine entropy and heat capacities values of the new GA groups. 

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