All Publications

  • Geometry optimization made simple with translation and rotation coordinates JOURNAL OF CHEMICAL PHYSICS Wang, L., Song, C. 2016; 144 (21)


    The effective description of molecular geometry is important for theoretical studies of intermolecular interactions. Here we introduce a new translation-rotation-internal coordinate (TRIC) system which explicitly includes the collective translations and rotations of molecules, or parts of molecules such as monomers or ligands, as degrees of freedom. The translations are described as the centroid position and the orientations are represented with the exponential map parameterization of quaternions. When TRIC is incorporated into geometry optimization calculations, the performance is consistently superior to existing coordinate systems for a diverse set of systems including water clusters, organic semiconductor donor-acceptor complexes, and small proteins, all of which are characterized by nontrivial intermolecular interactions. The method also introduces a new way to scan the molecular orientations while allowing orthogonal degrees of freedom to relax. Our findings indicate that an explicit description of molecular translation and rotation is a natural way to traverse the many-dimensional potential energy surface.

    View details for DOI 10.1063/1.4952956

    View details for Web of Science ID 000378923500010

    View details for PubMedID 27276946

  • Atomic orbital-based SOS-MP2 with tensor hypercontraction. I. GPU-based tensor construction and exploiting sparsity JOURNAL OF CHEMICAL PHYSICS Song, C., Martinez, T. J. 2016; 144 (17)


    We present a tensor hypercontracted (THC) scaled opposite spin second order Møller-Plesset perturbation theory (SOS-MP2) method. By using THC, we reduce the formal scaling of SOS-MP2 with respect to molecular size from quartic to cubic. We achieve further efficiency by exploiting sparsity in the atomic orbitals and using graphical processing units (GPUs) to accelerate integral construction and matrix multiplication. The practical scaling of GPU-accelerated atomic orbital-based THC-SOS-MP2 calculations is found to be N(2.6) for reference data sets of water clusters and alanine polypeptides containing up to 1600 basis functions. The errors in correlation energy with respect to density-fitting-SOS-MP2 are less than 0.5 kcal/mol for all systems tested (up to 162 atoms).

    View details for DOI 10.1063/1.4948438

    View details for Web of Science ID 000377711300015

    View details for PubMedID 27155629

  • Efficient implementation of effective core potential integrals and gradients on graphical processing units JOURNAL OF CHEMICAL PHYSICS Song, C., Wang, L., Sachse, T., Preiss, J., Presselt, M., Martinez, T. J. 2015; 143 (1)

    View details for DOI 10.1063/1.4922844

    View details for Web of Science ID 000357873900018

  • Analytic first derivatives of floating occupation molecular orbital-complete active space configuration interaction on graphical processing units JOURNAL OF CHEMICAL PHYSICS Hohenstein, E. G., Bouduban, M. E., Song, C., Luehr, N., Ufimtsev, I. S., Martinez, T. J. 2015; 143 (1)

    View details for DOI 10.1063/1.4923259

    View details for Web of Science ID 000357873900015