Default atomic masses and their rationale

Questions of type "How do I calculate xxx ?"
(Open discussion, limited support from the helpdesk.)

Moderators: Moderator, Global Moderator

Default atomic masses and their rationale

Postby agtonner » Fri Feb 22, 2019 3:55 pm


when looking at the default atomic masses used in VASP I saw that e.g. H is defined as exactly 1 amu when it should be 1.008 (
This might not look like much but it changes the frequency of vibrations by 10-30 wavenumbers.

I assume that the masses are all relative to 1^H instead of 1/12 12^C ?

Is there a reason those masses are chosen for VASP? Is there a reference for how these were obtained? Should it be changed to reach parity with IUPAC?

Thank you for your assistance.

Posts: 3
Joined: Wed Aug 25, 2010 12:39 pm
Location: Marburg, Germany

Return to Physics questions

Who is online

Users browsing this forum: No registered users and 0 guests