13楼: Originally posted by gemucai at 2012-08-02 18:56:11
我记得gulp是经典的紧束缚方法吧？朝出现虚频的方向改变原子位置试试。...

GULP is a program for performing a variety of types of simulation on materials using boundary conditions of 0-D (molecules and clusters), 1-D (polymers), 2-D (surfaces, slabs and grain boundaries), or 3-D (periodic solids). The focus of the code is on analytical solutions, through the use of lattice dynamics, where possible, rather than on molecular dynamics. A variety of force fields can be used within GULP spanning the shell model for ionic materials, molecular mechanics for organic systems, the embedded atom model for metals and the reactive REBO potential for hydrocarbons. Analytic derivatives are included up to at least second order for most force fields, and to third order for many.

3楼: Originally posted by gemucai at 2012-05-25 18:59:36
问题解决了。

跟大家分享一下我的解决方法，以后碰到有虚频的情况不妨增加smearing的宽度，即degauss的大小，效果很灵的。其实有时候根本不需要过度地优化，我优化到0.0000001ry/bohr也有很大虚频，但是degauss增 ...