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(May 16, 2021)

The ability to compute SCF and MP2 energies and forces at reduced cost makes dual-basis calculations
attractive for *ab initio* molecular dynamics simulations, which are described in Section 9.9.
Dual-basis BOMD has demonstrated
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1041
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J. Phys. Chem. A

(2010),
114,
pp. 11853.
Link
savings of 58%, even relative to state-of-the-art, Fock-extrapolated BOMD. Savings are further
increased to 71% for dual-basis RI-MP2 dynamics. Notably, these timings outperform estimates
of extended Lagrangian (“Car-Parrinello”) dynamics, without detrimental energy conservation
artifacts that are sometimes observed in the latter.
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J. Chem. Phys.

(2004),
121,
pp. 11542.
Link

Two algorithm improvements make modest but worthwhile improvements to dual-basis dynamics. First,
the iterative, small-basis calculation can benefit from Fock matrix extrapolation.
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J. Chem. Phys.

(2004),
121,
pp. 11542.
Link
Second, extrapolation of the response equations (“$Z$-vector” equations) for
nuclear forces further increases efficiency.
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Chem. Phys. Lett.

(2010),
500,
pp. 167.
Link
(See Section 9.9.)
Q-Chem automatically
adjusts to extrapolate in the proper basis set when DUAL_BASIS_ENERGY is activated.