TY - JOUR
T1 - Multilevel X-Pol
T2 - A fragment-based method with mixed quantum mechanical representations of different fragments
AU - Wang, Yingjie
AU - Sosa, Carlos P.
AU - Cembran, Alessandro
AU - Truhlar, Donald G
AU - Gao, Jiali
PY - 2012/6/14
Y1 - 2012/6/14
N2 - The explicit polarization (X-Pol) method is a fragment-based quantum mechanical model, in which a macromolecular system or other large or complex system in solution is partitioned into monomeric fragments. The present study extends the original X-Pol method, where all fragments are treated using the same electronic structure theory, to multilevel representations, called multilevel X-Pol, in which different electronic structure methods are used to describe different fragments. The multilevel X-Pol method has been implemented into a locally modified version of Gaussian 09. A key ingredient that is used to couple interfragment electrostatic interactions at different levels of theory is the use of the response density for the post-self-consistent-field energy. (The response density is also called the generalized density.) The method is useful for treating fragments in a small region of the system such as a solute molecule or the substrate and amino acids in the active site of an enzyme with a high-level theory, and the fragments in the rest of the system by a lower-level and computationally more efficient method. Multilevel X-Pol is illustrated here by applications to hydrogen bonding complexes in which one fragment is treated with the hybrid M06 density functional, Møller - Plesset perturbation theory, or coupled cluster theory, and the other fragments are treated by Hartree - Fock theory or the B3LYP or M06 hybrid density functionals.
AB - The explicit polarization (X-Pol) method is a fragment-based quantum mechanical model, in which a macromolecular system or other large or complex system in solution is partitioned into monomeric fragments. The present study extends the original X-Pol method, where all fragments are treated using the same electronic structure theory, to multilevel representations, called multilevel X-Pol, in which different electronic structure methods are used to describe different fragments. The multilevel X-Pol method has been implemented into a locally modified version of Gaussian 09. A key ingredient that is used to couple interfragment electrostatic interactions at different levels of theory is the use of the response density for the post-self-consistent-field energy. (The response density is also called the generalized density.) The method is useful for treating fragments in a small region of the system such as a solute molecule or the substrate and amino acids in the active site of an enzyme with a high-level theory, and the fragments in the rest of the system by a lower-level and computationally more efficient method. Multilevel X-Pol is illustrated here by applications to hydrogen bonding complexes in which one fragment is treated with the hybrid M06 density functional, Møller - Plesset perturbation theory, or coupled cluster theory, and the other fragments are treated by Hartree - Fock theory or the B3LYP or M06 hybrid density functionals.
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U2 - 10.1021/jp212399g
DO - 10.1021/jp212399g
M3 - Article
C2 - 22428657
AN - SCOPUS:84862299174
SN - 1520-6106
VL - 116
SP - 6781
EP - 6788
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 23
ER -