### Nanoscale Simulations, Wolfgang-Pauli-Strasse 27, ETH Zurich, Switzerland

## Exploring Frontiers in Sampling, Large Scale Models and Electron Correlation Using Petascale Computing and CP2K

##### Monday, March 9, 2015, 4:00 PM

##### Chevron 150

Already with modest computer resources, GGA DFT simulations of models containing a few hundred atoms can contribute greatly to chemistry, physics and materials science. With the advent of petascale resources, new length, time and accuracy scales can be explored. We will discuss how linear scaling techniques make structural relaxation and time propagation possible for systems containing 10’000s of atoms possible [1]. Second, with a focus on improving the accuracy of condensed phase simulations beyond GGA DFT, we discuss recent progress made towards efficient 4th and 5th rung density functionals. In particular, a well parallelized implementation of a novel algorithm to compute four center integrals over molecular states (RI-GPW) allows for many-body perturbation theory (MP2, RPA) calculations on a few hundred atoms [2]. Third, we will illustrate how long Monte Carlo simulations of condensed phases can be combined with electronic structure theory to compute properties that require extensive phase space averaging. We will present the application of these methods to liquid water [3], water ice [4] and polarons in TiO2 [5], as well as their implementation the freely available CP2K program [6].

**[1]** Joost VandeVondele, Urban Borstnik, Jürg Hutter, JCTC 8, 3565 (2012).

**[2]** Mauro Del Ben, Jürg Hutter, and Joost VandeVondele, JCTC 9, 2654 (2013).

**[3]** Mauro Del Ben, Mandes Schönherr, Jürg Hutter, and Joost VandeVondele JPCL 4, 3753 (2013).

**[4]** Mandes Schönherr, Ben Slater, Jürg Hutter, and Joost VandeVondele JPCB 118, 590 (2014).

**[5]** Clelia Spreafico, and Joost VandeVondele, PCCP 16, 26144 (2014).

**[6]** http://www.cp2k.org/