Ba-induced quasi-one-dimensional reconstructions of the Si( 1 1 1) surface have been investigated by low energy electron diffraction (LEED) and scanning tunneling microscopy (STM). While the 3 x '2' surface shows double-periodicity along the stripes in STM images consistent with half-order streaks observed in LEED patterns, no sign of the double-periodicity along the chain direction was detected for the 5 x 1 surface. The 5 x stripes in STM images show internal structures with multiple rows. The two rows comprising the boundaries of a 5 x stripe in the filled-state STM image are found to have 3a x root 3/2 spacing across the stripe. The observation of the successive 3 x and 2 x spacings between the boundary rows supports a structural model proposed for the Ba-induced 5 x 1 Si reconstruction composed of honeycomb chains and Seiwatz chains. The highest coverage 2 x 8 surface does not reveal a quasi-1D row structure in STM images. (C) 2008 Elsevier B.V. All rights reserved.