We have conducted a spectroscopic survey of 78 starbursting infrared-luminous galaxies at redshifts up to z = 0.5 .
We use moderate-resolution spectroscopy of the Na i D interstellar absorption feature to directly probe the neutral phase of outflowing gas in these galaxies .
Over half of our sample are ultraluminous infrared galaxies that are classified as starbursts ; the rest have infrared luminosities in the range \log ( L _ { \mathrm { IR } } / L _ { \sun } ) = 10.2 - 12.0 .
The sample selection , observations , and data reduction are described here .
The absorption-line spectra of each galaxy are presented .
We also discuss the theory behind absorption-line fitting in the case of a partially-covered , blended absorption doublet observed at moderate-to-high resolution , a topic neglected in the literature .
A detailed analysis of these data is presented in a companion paper .