Thanks a lot Sam!
That was really useful 
Unfortunately I am totally non-familiar with the OriginLab script syntax. Maybe someone could help me out with the code to loop over colums (a link to a similar example code would also be fine).
Thats what I planned to do (I know its rather pseudo-code than real OriginLab script 
):
void FrequencyNormalization(Worksheet& ws, const int& fnum)
{
new vector(fnum) normBases; //allocate the space for a new array to store 1 double value for each frequency
loop(i, 1, fnum)
{
normBases.add(ws.Col(i)[1]); //for each column store the first value in the normBases array
}
loop(ii, 1, fnum)
{
ws.Col(ii) /= normBases(ii); //Normalize all colums by dividing each value by the corresponding value of the normBases array
}
}
