## 3 Further Tests of SET Catalysis
### Cyanamide Test  
[PERSON] left behind not only his famous report [11; 12] on the formation of amino acids by the exposure of simpler substances (e.g., CH\({}_{4}\), NH\({}_{3}\), etc.) to electric discharges. He also left many vials containing the results of other investigations. Most of these samples were not analyzed until the first decades of the 21 st century. Then, some of his previous collaborators found the remains and started to publish the content of [PERSON]'s notebooks [27]. The strategy of [PERSON] as well as his followers was to combine the well-established amino acid synthesis by electric discharge with a parallel exposure of the reaction mixture to cyanamide, H\({}_{2}\)N-CN [27]. This substance was added intermittently to the reacting gas mixture [27]. The result was that many amino acids were formed (probably by the electric discharge effect), along with dipeptide combinations of many of these acids (e.g., gly-gly, gly-ala, glu-gly). We will now test if the SET model works for these reactions equally well as in the previously discussed cases. For this purpose, we use glycine as the model substance. Our starting view is that the reaction proceeds in two stages: the first reaction is the formation of amino acids as found by [PERSON] [11], the second reaction is the formation of dipeptides--very much like what is described above in Section 2. In order to follow this plan, we first need to know infrared data for cyanamide [28], and secondly infrared data for (free) glycine [29]. Thus equipped, we suggest following the path of the procedure applied in the above chapters. This means that we give the major role to the \(\varrho_{w}\)(NH\({}_{2}\)) vibration of the glycine molecule, and start looking for a counterpart in the spectrum of the cyanamide molecule. Such comparisons are made in Table 3.  
The winner in this contest is the 3261 cm\({}^{-1}\) vibration of cyanamide. As all other of the tabulated vibrations are denoted as weak or possibly medium, this very strong absorber--and consequently, very strong emitter--will do a good job of supplying the glycine vibrator with many quanta that will stimulate the NH\({}_{2}\) wagging and consequently work for the expulsion of one of the two hydrogen atoms, as described in Section 2. Following the treatment of the previous systems, COS and ferricyanide complexes, we find that one quantum of the excited \"activating agent\", 3261 cm\({}^{-1}\), can be compared with three quanta of the NH\({}_{2}\) wagging of glycine (1069 cm\({}^{-1}\); cf. Table 3). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Conditions** & \begin{tabular}{c} **Glycine Vibration** \\ **cm\({}^{-1}\)[29]** \\ \end{tabular} & **Factor** & \
\begin{tabular}{c} **Resulting** \\ **Product cm\({}^{-1}\)** \\ \end{tabular} &
\begin{tabular}{c} **Cyanamide** \\ **Vibration cm\({}^{-1}\)[28]** \\ \end{tabular} & **Diff\%** \\ \hline Acid & Not present & & & & \\ Neutral & 882 (m) & 1 & 882 & 937 (v w) & 6.2 \\  & & 2 & 1764 & 1576 (m) & 10.7 \\  & & 3 & 2646 & 2731 (v w) & 3.2 \\ Alkaline & 1069 (w) & 1 & 1069 & 1094 (w) & 2.3 \\  & & 2 & 2138 & 2199 (v w) & 2.9 \\  & & 3 & 3207 & 3261 (v s) & 1.7 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Comparison between vibration frequencies of \(\varrho_{w}\)(NH\({}_{2}\)) of glycine [29] and those cyanamide vibrations [28] that best agree with the glycine vibration. The difference between columns 5 and 4, in absolute numbers (Diff), is expressed as per cent of the \"resulting product\". Copyrights for these data relate to those Of Ref [28] and Ref [29]. As \(3\times 1069=3207\), we get a measure of a possible resonance as \(3261/3207=1.017\), which is as good as the corresponding ratios reported above. Thus, we can confirm the reasoning of [PERSON], given that the prebiotic atmosphere contained H\({}_{2}\)N-CN. One can further note that, as [PERSON] et al. [27] pointed out, the reactive amino acid species is H\({}_{3}\)N\({}^{+}\)C(RR') COO\({}^{-}\).