Professor (physicist) said this function is called correlation function. Than I talked to someone from mathematics department and he said it's some sort of discrete convolution, so it really depends on person, how he/she calls it. ListConvolve and ListCorrelate should give same results when given right parameters. I think there is something strange about my data (linked in previous post), because I also have some other data and when I use them I get correct (same) results. I tried all the code in above answers and with given data nothing works. I think I'll just use fourier transform method because it returns symmetric data (which is correct) in contrast to ListCorrelate and ListConvolve which return asymmetric data. Thank you all.