Change the equation of the Gauss bell

My goal is to draw the absorption peaks of Lambert-Beer-Bouguer graph which, ideally, have the shape of a Gaussian. I would like to make sure that these peaks all have the same width, which in Gauss’s equation depends on sigma, and I could change its height.
Something like

gauss{9}{1}

Where 9 is the symmetry axis (mu) and 1 is the height of the peak.
How can I modify the equation to achieve this?

newcommandgauss[2]{1/(sqrt(2*pi))*exp(-((x-#1)^2)/(2*#2^2))} % Gauss function, parameters mu and sigma