Strong anisotropic angular distributions of the atomic ions Im+ (m = 1-6) and Cn+ (n = 1-2) have been observed when CH3I is irradiated by 110 fs, 8 10 nm laser pulses at an intensity of 10(15) W/cm(2). A comparison was made of the fragmental ions between the linearly polarized laser pulses and circularly polarized laser pulses, and the variation of the angular widths for different charged exploding ions was studied. Moreover, a double pulse experiment with crossed polarization was also performed. The results clearly demonstrate that a geometric alignment is the dominant mechanism for CH3I under the experimental conditions. (c) 2005 Elsevier B.V. All rights reserved.