Hi. I am using the Gaussian bond and angle styles in a simulation. Comparing the expression in the LAMMPS documentation to the original paper (J. Polym. Sci. B Polym. Phys. 43, 871 (2005)), there appears to be a difference in the exponents of a factor of two. The source code seems to indicate that the factor of 2 is used in the computation. Just wanted to check before fitting the wrong functional form!
This appears to be a typo in the documentation, the factor of 2 is in the source code:
Same for angle:
I have checked the output from
bond_write for bond style gaussian against the expression in the docs and can confirm that the factor 2 is missing (and a right parenthesis too many).
This will be updated with the next LAMMPS patch release (probably next month).
Hi,I have meet the same problem these days, but I don’t know whether my
problem is because of this missing factor 2, I compared the gaussian type (n=1) and transformed it to harmonic type ‘K(l-l0)^2’, ignored energy when L=L0, but bond length in gaussian simulation have smoe much longer bond length as 90A rather than 4.8A in harmonic simulation. Could you
please help me?
else I also see that original paper, I still don’t konw why they normalized by P/r2 or P/sin(theta)
Please see my response here Bond_style Gaussian question in simulation (n=1,compared with harmonic) - #6 by akohlmey