A facile method for investigating the orientation of amphiphiles in the LB
films using IR transmission and reflection-absorption spectroscopy (RAS) wa
s presented. This method does not require the estimation of the enhancement
factor in the RAS measurements or that of the difference in quantities of
the molecules in the LB films on different substrates. The application of t
he present method to the actual LB films gave better results compared with
the conventional method.