LC-wPBE problem

Just Got Here

3:35:12 PM PDT - Mon, Apr 18th 2016
Hi I am trying to use the LC-wPBE in my calculation. From the documentation, the input is as following: xc xwpbe 1.00 cpbe96 1.0 hfexch 1.00 cam 0.3 cam_alpha 0.00 cam_beta 1.00 However, it says below that the cam_alpha and cam_beta are parameters that control the amount of short-range DFT and long-range HF. For LC-wPBE it should be 100% short-range DFT and 100% long-range HF which means cam_alpha and cam_beta should both be 1. Did this input use any different code so that cam_alpha is actually 1 minus the coefficient? Thank you. Best, Han

Forum Regular

10:31:39 AM PDT - Tue, Apr 19th 2016
Hi Han, Unlike the traditional definition of global hybrid functionals, the way we handle range-separated forms is we define full magnitudes in the first line. The behavior of the range-separated functional as a function of distance is controlled by the second line (cam …) Here, the cam_beta controls the long-range asymptotic behavior of the HF part. The cam term (the exponent term) controls where the short-range DFT turns off and where the long-range HF turns on. Best, -Niri