How to change the space between columns when drawing multiple strokes in pandas?

Question

I draw several barplots using the following call to DataFrame.plot:

df.plot(kind='bar',
         stacked=False, 
         figsize=figsize,
         rot=0,
         alpha=0.5, 
         width=width)

However, I want to increase the size between the columns in each category. How can I achieve this?