TURBOMOLE manual
v8.0

9.1 Functionalities of mpgrad, and ricc2, and pnoccsd

Functionalities of mpgrad:

  • Calculation of MP2 energies and/or MP2 gradients for RHF and UHF wave functions.

  • The frozen core approximation (possibility to exclude low-lying orbitals from the MP2 treatment) is implemented only for MP2 energies.

  • Exploitation of symmetry of all point groups.

  • Can be used sequentially or MPI-parallel.

  • Can be combined with the COSMO solvation model (see section 9.7 and chapter 21.2 for details). (Presently restricted to sequential calculations.)

Functionalities of ricc2 at the MP2 level:

  • Calculation of MP2 energies and/or gradients for RHF and UHF wave functions within the RI approximation (RI-MP2). In geometry optimizations and vibrational frequency calculations (with NumForce) it can be combined with RI-JK-SCF for the Hartree-Fock reference calculation.

  • The frozen core approximation is implemented for both energies and gradients.

  • RI-MP2 needs optimised auxiliary basis sets, which are available for most standard basis sets as e.g. SVP, TZVP, TZVPP, QZVPP as well as for the (aug-)cc-p(wC)VXZ (X = D, T, Q, 5) basis set series (for Al–Ar also for the (aug-)cc-p(wC)V(X+d)Z series and for \(p\)-block elements Ga–Rn also the respective ECP basis set series (-pp)).

  • Exploitation of symmetry for all point groups for MP2 energies and gradients.

  • Can be combined with the COSMO solvation model, see chapter 21.2 for details on COSMO and section 9.7 for the options available for COSMO-MP2.

  • Can be combined the polarizable embedding (PE and PE(ECP)) and frozen density embedding (FDE), see chapter 10.9 for details.

  • Runs sequentially and parallel (with MPI, OpenMP and hybrid MPI/OpenMP)

  • Contains an implementation of explicitly correlated MP2-F12 methods (present­ly restricted to energies and the \(C_1\) point group).

  • Can for open-shell calculations be used with UHF and single-determinant high-spin ROHF reference wavefunctions. (ROHF-MP2 presently limited to energies.)

  • Energies and gradients for the spin-component scaled SCS- and SOS-MP2 approaches, including a Laplace-transformed implementation of SOS-MP2 with \({\cal O}({\cal N}^4)\) scaling computational costs.

  • Static polarizabilities (currently restricted to closed-shell reference wavefunctions and the sequential and SMP versions; cannot yet be combined with spin-component scaling), see Chapter 10.5 for a description of the input

  • See Chapter 10 for further details.

Functionalities of pnoccsd:

  • Currently restricted to CCSD, CCSD(T0), CCSD(T), MP2 and DFT double hybrid (e.g. B2PLYP) single point energy calculations with a RHF or UHF reference determinant and the \(C_1\) point group.

  • Runs sequentially and parallel (MP2 with MPI, OpenMP and hybrid MPI/OpenMP, CCSD and beyond with OpenMP).

  • Contains an implementation of explicitly correlated PNO-MP2-F12 methods.

  • See Section 12 for further details.

9.1.1 How to quote

  • For calculations with mpgrad:
    Semi-direct MP2 Gradient Evaluation on Workstation Computers: The MPGRAD Program. F. Haase and R. Ahlrichs; J. Comp. Chem. 14, 907 (1993).

  • For calculations with ricc2:
    CC2 excitation energy calculations on large molecules using the resolution of the identity approximation. C. Hättig and F. Weigend;

  • for MPI parallel calculations with ricc2 in addition:
    Distributed memory parallel implementation of energies and gradients for second-order Møller-Plesset perturbation theory with the resolution-of-the-identity approximation. Christof Hättig, Arnim Hellweg, Andreas Köhn, Phys. Chem. Chem. Phys. 8, 1159-1169, (2006).

  • for MP2-F12 calculations in addition:
    The MP2-F12 Method in the TURBOMOLE Programm Package. Rafal A. Bachorz, Florian A. Bischoff, Andreas Glöß, Christof Hättig, Sebastian Höfener, Wim Klopper, David P. Tew, J. Comput. Chem. 32, 2492–2513 (2011).

  • for \({\cal O}({\cal N}^4)\)-scaling LT-SOS-MP2 calculations:
    Scaled opposite-spin CC2 for ground and excited states with fourth order scaling computational costs. Nina O. C. Winter, Christof Hättig, J. Chem. Phys., 134, 184101 (2011) and Scaled opposite-spin second order Møller–Plesset correlation energy: An economical electronic structure method. Y., Jung, R.C. Lochan, A.D. Dutoi, and M. Head-Gordon, J. Chem. Phys., 121, 9793 (2004).

  • for SCS-MP2 calculations:
    S. Grimme, J. Chem. Phys. 118, 9095 (2003).

  • for RI-MP2 polarizabilities:
    Large scale polarizability calculations using the approximate coupled cluster model CC2 and MP2 combined with the resolution-of-the identity approximation. Daniel H. Friese, Nina O. C. Winter, Patrick Balzerowski, Raffael Schwan, Christof Hättig, J. Chem. Phys., 136, 174106 (2012).

  • for PNO-MP2 calculations: A \({\cal O}({\cal N}^3)\)-scaling PNO-MP2 method using a hybrid OSV-PNO approach with an iterative direct generation of OSVs. Gunnar Schmitz, Benjamin Helmich, Christof Hättig, Mol. Phys. 111, 2463–2476, (2013). and Principal Domains in Local Correlation Theory. David. P. Tew, J. Chem. Theory Comput. 15, 6597 (2019)

  • for explicitly correlated PNO-MP2-F12 calculations: Explicitly correlated PNO-MP2 and PNO-CCSD and its application to the S66 set and large molecular systems. Gunnar Schmitz, Christof Hättig, David Tew, Phys. Chem. Chem. Phys. 16, 22167–22178 (2014).