AIMNet2

AIMNet2 is a neural network potential that provides broad element coverage (14 elements) with ωB97M-D3BJ accuracy. It is one of only two models in MAPLE (along with UMA) that natively supports charged and open-shell molecular systems.

Variants

Model	Keyword	Elements	Description
AIMNet2	`aimnet2`	H, B, C, N, O, F, Si, P, S, Cl, As, Se, Br, I	Standard variant with ωB97M-D3BJ accuracy
AIMNet2-NSE	`aimnet2nse`	H, B, C, N, O, F, Si, P, S, Cl, As, Se, Br, I	Variant including nuclear spin-orbit effects for heavy elements

Charge and Spin Support

AIMNet2 natively handles charged species and different spin multiplicities. Specify charge and multiplicity in the coordinate block:

#model=aimnet2
#opt(method=lbfgs)

-1 1
C    0.000000    0.000000    0.000000
O    1.250000    0.000000    0.000000
O   -1.250000    0.000000    0.000000

The first line specifies charge multiplicity (here: charge = −1, multiplicity = 1 for a formate anion).

Implicit Solvation

AIMNet2 supports GBSA implicit solvation correction. QEq charges are computed automatically:

#model=aimnet2
#solv(method=gbsa, implicit=water)
#opt(method=lbfgs)

-1 1
C    0.000000    0.000000    0.000000
O    1.250000    0.000000    0.000000
O   -1.250000    0.000000    0.000000

Usage Examples

Optimization with heavy elements (Br, I)

#model=aimnet2
#device=gpu0
#opt(method=lbfgs)

0 1
C    0.000000    0.000000    0.000000
Br   1.940000    0.000000    0.000000
H   -0.390000    0.000000    1.028000
H   -0.390000    0.890000   -0.514000
H   -0.390000   -0.890000   -0.514000

NSE variant for systems with heavy-element spin-orbit effects

#model=aimnet2nse
#device=gpu0
#opt(method=lbfgs)

0 1
C    0.000000    0.000000    0.000000
I    2.140000    0.000000    0.000000
H   -0.390000    0.000000    1.028000
H   -0.390000    0.890000   -0.514000
H   -0.390000   -0.890000   -0.514000

Limitations

No D4 dispersion. The ωB97M-D3BJ training already includes dispersion corrections.
No periodic systems. AIMNet2 does not support periodic boundary conditions.
14 elements only. Systems with elements outside the supported set (e.g., transition metals) require uma instead.