SIO2 DATA, from Palik HOC Vol. 1, p. 759
ANGSTROMS
NK
2066    1.543   0
2267    1.52276 0
2483    1.50841 0
2652    1.50004 0
2803    1.49404 0
3022    1.48719 0
3303    1.48053 0
3611    1.47512 0
4047    1.46961 0
4358    1.46669 0
4678    1.46429 0
5086    1.46187 0
5461    1.46008 0
5770    1.45885 0
5893    1.45841 0
6438    1.45671 0
6678    1.45608 0
7065    1.45515 0
8521    1.45248 0
8944    1.45185 0
10140   1.45025 0
11286	1.44888	0
13622	1.44621	0
14695	1.44497	0
16606	1.44267	0
17091	1.44205	0
20581	1.43722	0