Basis Sets and Pseudopotentials
For QMC calculations, we need to use pseudopotentials optimized specifically for QMC, and basis sets optimized to be used with these pseudopotentials. Here, we use the Burkatzki-Filippi-Dolg (BFD) ones except for hydrogen (the hydrogen pseudo on the website is too soft and not sufficiently accurate).
QP can read basis sets and pseudopotentials from files in GAMESS format, if the files exist in the current directory. Otherwise, it will try to look into its own database of basis sets and pseudopotentials.
BFD Pseudopotential
Store the pseudopotential parameters in a file named PSEUDO:
H GEN 0 0
3
1.000000000000 1 25.000000000000
25.000000000000 3 10.821821902641
-8.228005709676 2 9.368618758833
O GEN 2 1
3
6.00000000 1 9.29793903
55.78763416 3 8.86492204
-38.81978498 2 8.62925665
1
38.41914135 2 8.71924452
Double-Zeta basis set
Store the basis set parameters in a file named BASIS:
HYDROGEN
s 3
1 6.46417546 0.063649375945
2 1.13891461 0.339233210576
3 0.28003249 0.702654522063
s 1
1 0.05908405 1.00000000
p 1
1 0.51368060 1.00000000
OXYGEN
s 9
1 0.125346 0.055741
2 0.268022 0.304848
3 0.573098 0.453752
4 1.225429 0.295926
5 2.620277 0.019567
6 5.602818 -0.128627
7 11.980245 0.012024
8 25.616801 0.000407
9 54.775216 -0.000076
s 1
1 0.258551 1.000000
p 9
1 0.083598 0.044958
2 0.167017 0.150175
3 0.333673 0.255999
4 0.666627 0.281879
5 1.331816 0.242835
6 2.660761 0.161134
7 5.315785 0.082308
8 10.620108 0.039899
9 21.217318 0.004679
p 1
1 0.267865 1.000000
d 1
1 1.232753 1.000000