Table 1.

Central frequencies and fitted linewidths (full width at half-maximum) for the C≡N stretching bands shown in Fig. 2

Probe site	Unbound frequency/cm−1	Unbound line width/cm−1	Frequency with XD/cm−1	Line width with XD/cm−1
S407C∗	2163.4	13.0	2163.2	13.5
L496C∗	2163.3	11.7	2163.2	13.6
S491C∗	2163.1	12.4	2163.0	14.0
V517C∗	2163.4	11.3	2162.4	11.0

All reported values are ±0.2 cm⁻¹.