  We report new experimental hyperfine structure (HFS) constants of neutral and
singly ionized scandium (Sc I and Sc II). We observed spectra of Sc-Ar and
Sc-Ne hollow cathode discharges in the region 200-2500 nm (50,000-4000
cm$^{-1}$) using Fourier transform spectrometers. The measurements show
significant HFS patterns in 1431 spectral lines fitted in our 12 spectra given
in Table 1. These were fitted using the computer package Xgremlin to determine
the magnetic dipole hyperfine interaction constant (A) for 185 levels in Sc i
and 6 levels in Sc II, of which 80 Sc I levels had no previous measurements.
The uncertainty in the HFS A constant is between 1 $\times$ 10$^{-4}$ and 5
$\times$ 10$^{-4}$ cm$^{-1}$.
