| _SECTION_PARAMETERS_ | |
| activates the functional | |
| This optional keyword expects a logical | |
| This keyword behaves as a switch T . Default value: F | |
| FUNCTIONAL | |
| FUNCTIONAL PW86X | |
| Which one of the XGGA functionals should be used | |
| This optional keyword expects a keyword. Default value: BECKE88X | |
| valid keywords: BECKE88X, PW86X, PW91X, PBEX, REV_PBEX, OPTX |