Hydrogen bonding exchange approximations

D. Discussion on the Exchange Approximation in the Absence of a Hydrogen Bond... 

Figure 12. Hydrogen bond involving a Fermi resonance damping parameters switching the intensities. The lineshapes were computed within the adiabatic and exchange approximations. Intensities balancing between two sub-bands are observed when modifying the damping parameters (a) with y0 =0.1, and y5 = 0.8 (b) with ya = ys = 0.8 (c) with yB — 0.8 and ys — 0.1. Common parameters oto = 1, A = 150cm, 2g)5 = 2850cm-1, and T = 30 K.

Figure 7. Top The formation of heterodimer 6-7 from softballs 6 6 and 7-7. Bottom Two SN2-like window" mechanisms for guest exchange in the softballs. Attack in an approximate 90°C angle between incoming and leaving guest is favored over backside attack energetically - only ten instead of twelve hydrogen bonds are broken - and entropically - statistically, there are four ways to open two vicinal windows, but only two ways to open windows opposite to each other.

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