Previous Thread
Next Thread
Print Thread
Page 2 of 2 1 2
Re: Q-Chem webinars 2012-2013
Yihan Shao #32871 10/28/13 08:43 PM
Joined: Jun 2009
Posts: 22
Y
Forum Member
OP Offline
Forum Member
Y
Joined: Jun 2009
Posts: 22
Title: "Tune your range separated hybrid and breathe some life into your orbital energies"
Presenters: Prof. Roi Baer, Hebrew University of Jerusalem and Dr. Tamar Stein, Rice University
When: 1:00 pm EST on Wednesday, November 6, 2013
Duration: 1 hour
Registration: https://attendee.gotowebinar.com/register/4499889129582425345

Summary:

Electron dynamics in e.g. photovoltaic, photosynthesis or molecular electronic systems is described using the concept of a quasiparticle (QP). A QP is the effective negative (positive) particle formed when a real electron is added to (or removed from) a system of electrons.

Loosely speaking, the QP is the bare particle (hole) together with the charge perturbation it stirs up in the surrounding electron (polarization) cloud.

The first thing needed to understand electron dynamics is to know the QP energies in these systems. Such energies can be obtained by solving the Dyson equation, as done in the so-called GW method. However, application of GW is difficult because of its high scaling of CPU time and memory with system size. Typically, a GW calculation requires an effort comparable to that of the CCSD method.

DFT helps us describing the static aspects of electronic systems. TDDFT helps us with electron dynamics. But both theories do not offer enough of the insight we require. The main reason for this is that in actual applications the orbital energies of DFT are far removed from the correct value of the QP energies. This happens because of imperfections in the underlying approximate functionals but also for more fundamental reasons, not associated with approximations.

We briefly discuss these issues in the first part of the talk. We show examples where knowing the QP energies offers a simple explanation to a complicated looking behavior. We also analyze the theoretical reasons that various DFT methods orbital energies are far removed from QP energies.

The second half of the talk is more practical. We demonstrate using QCHEM how a first-principles tuning procedure of the range parameter in a range separated hybrid can bring the DFT orbital energies close to the QP energies. We also explain why such a procedure is crucial not only for insight but also for describing quantitatively the charge transfer dynamics in molecular complexes, light harvesting systems and molecular junctions (Phys. Rev. Lett. 109, 226405, 2012, http://link.aps.org/doi/10.1103/PhysRevLett.109.226405).

About the Presenters:

Prof. Roi Baer obtained his Ph.D. from the Hebrew University of Jerusalem in 1996, and was a Postdoctroal fellow (with Prof. Martin Head-Gordon) at UC Berkeley from 1996 to 1998. Then he returned to Hebrew U where he is now a Professor and the director of the Fritz Haber Center for Molecular Dynamics, Chaim Weizmann Institute of Chemistry. He is well known for his many contributions to the field of Theoretical Chemistry (http://www.fh.huji.ac.il/~roib/), especially the development of time-dependent density functional methods for studying charge transfer dynamics. Prof. Baer was an Associate Editor of Theoretical Chemistry Accounts, and also serves on the the editorial advisory committees for several other journals, including the Journal of Physical Chemistry and Annual Reviews of Physical Chemistry. Dr. Tamar Stein did Ph.D. thesis with Prof. Baer, and is now a postdoctoal fellow at Rice University (with Prof. Gustavo Scuseria).


Last edited by Yihan Shao; 10/28/13 08:49 PM.
Re: Q-Chem webinars 2012-2013
Yihan Shao #33416 02/10/14 07:02 PM
Joined: Jun 2009
Posts: 22
Y
Forum Member
OP Offline
Forum Member
Y
Joined: Jun 2009
Posts: 22
Title: Beyond critical points: Ab initio dynamics and sampling in Q-Chem
Presenter: Prof. Ryan P. Steele, University of Utah
When: 1:00 pm EST on Wednesday, February 19, 2014
Duration: 1 hour
Registration: https://attendee.gotowebinar.com/register/1047688702479653378

Summary:

This webinar will cover the methodology available to Q-Chem users for making molecules move. While the “bread and butter” of Q-Chem remains its ability to solve for static electronic properties, many other quantities of interest involve the motion of nuclei. Real-time dynamics, anharmonic spectroscopy, and thermodynamic ensembles require the user to move beyond critical points and explicitly include non-local nuclear motion. The webinar will address features available in Q-Chem for both classical and quantum mechanical nuclear motion, including new features unique to Q-Chem that notably accelerate calculations for dynamics and sampling.

About the Presenter:

Ryan P. Steele is an assistant professor of chemistry in the Henry Eyring Center for Theoretical Chemistry at the University of Utah. His research group develops new electronic structure theory methods in the context of chemical dynamics, spectroscopy, and catalysis. This focus leads to applications in solar energy catalysis, biological ions, and fundamental studies of ion/radical solvation.

Re: Q-Chem webinars 2012-2013
Yihan Shao #33547 03/11/14 08:11 PM
Joined: Jun 2009
Posts: 22
Y
Forum Member
OP Offline
Forum Member
Y
Joined: Jun 2009
Posts: 22
Title: Exploring Reaction Pathways using Quantum Mechanical/Molecular Mechanical Free Energy Simulations with Q-Chem and CHARMM: Application to Biochemical Reactions
Presenter: Abir Ganguly, University of Illinois at Urbana-Champaign
When: 1:00 pm EST on Wednesday, March 26, 2014
Duration: 1 hour
Registration: https://attendee.gotowebinar.com/register/2492938463803940865

Summary:

Characterizing the free energy pathway of a chemical reaction can provide valuable information related to the mechanism, kinetics and thermodynamics of the reaction. In the case of complex biological systems, this can be a challenging task due to the multi-dimensional nature of the reaction pathway and the lack of a priori knowledge of the relevant reaction coordinates. This webinar will discuss the characterization of the multidimensional free energy surfaces associated with biochemical reactions and the identification of favorable reaction pathways using quantum mechanical/molecular mechanical (QM/MM) free energy simulations with Q-Chem and CHARMM. The free energy surfaces are generated by combining a finite temperature string method with umbrella sampling simulations.

About the Presenter:

Abir Ganguly is a graduate student in the Sharon Hammes-Schiffer research group at the University of Illinois at Urbana-Champaign. He is part of a team that has the general interest of understanding enzymatic processes with particular emphasis on the role of hydrogen bonding, hydrogen tunneling, electrostatics, and motion in enzyme reactions. Specifically, his graduate research has focused on understanding the different aspects of chemistry of small, self-cleaving RNA enzymes, or ribozymes, using a variety of computational tools.

Re: Q-Chem webinars 2012-2013
Yihan Shao #33966 05/21/14 02:06 PM
Joined: Jun 2009
Posts: 22
Y
Forum Member
OP Offline
Forum Member
Y
Joined: Jun 2009
Posts: 22
Title: ADC in Q-Chem: A Versatile Module for Excited, Ionized and Electron-Attached States
Presenter: Prof. Dr. Andreas Dreuw, Chair of Theoretical and Computational Chemistry, Interdisciplinary Center for Scientific Computing, Unversity of Heidelberg
When: 1:00 pm EDT on Wednesday, May 28, 2014
Duration: 1 hour
Registration: https://attendee.gotowebinar.com/register/2239939740204277505

Summary:

ADC is a perturbation theoretical approach that allows for the direct computation of excitation energies, ionization potentials and electron affinities. In this webinar, the basic algebraic expressions of ADC will be derived and the mathematical advantages of the method will be highlighted. Main focus will be put on ADC for excited electronic states, and the second-order approaches ADC(2)-s and ADC(2)-x will be introduced, and the potential of the recently implemented third-order ADC(3) will be demonstrated. Beyond the computation of excitation energies and oscillator strengths, the ADC program gives access also to excited state properties like, state-to-state transition dipole moments, spin-orbit coupling elements and two-photon absorption. Pilot implementations of ADC for direct computation of ionization potentials and electron affinities will be introduced, and first results shown.

About the Presenter:

Dr. Andreas Dreuw is one of the leading experts in excited states method development and simulations. He received his Ph.D. from the University of Heidelberg in 2001. After a postdoctoral study at the University of California at Berkeley and Habilitation at the University of Frankfurt, he returned to the University of Heidelberg in 2011, where he is now the Chair of Theoretical and Computational Chemistry He has received many honors, including the Outstanding Young German Scientist Award of the Lise Meitner-Minerva Center of Computational Quantum Chemistry and the title of Heisenberg fellow of the DFG (2009-2011).

Re: Q-Chem webinars 2012-2013
Yihan Shao #34048 06/13/14 12:51 PM
Joined: Jun 2009
Posts: 22
Y
Forum Member
OP Offline
Forum Member
Y
Joined: Jun 2009
Posts: 22
Title: Q-Chem 4.2: An Engine for Innovation
Presenters: (in first-name alphabetical order)
Prof. Anna Krylov, University of Southern California
Prof. Daniel Lambrecht, University of Pittsburgh
Prof. John Herbert, Ohio State University
Dr. Zhengting Gan, Q-Chem, Inc.

When: 1:00 pm EDT on Wednesday, June 25, 2014
Duration: 1 hour
Registration: https://attendee.gotowebinar.com/register/4576823062742201090

Summary:
This webinar covers some of the most exciting new features and new improvements in the recent Q-Chem 4.2 release, and it consists of short presentations from four key developers of Q-Chem. Prof. Anna Krylov will provide a brief summary of the latest advances to our CCSD and EOM-CCSD module. Prof. Daniel Lambrecht will demonstrate the density embedding methods from his group. Prof. John Herbert will introduce his XSAPT methods for homogeneous QM/MM calculations on molecular clusters. Finally, Dr. Zhengting Gan will review Q-Chem's parallel capabiity for DFT calculations, which has been significantly improved thanks to his recent OpenMP implementations.

Presenters:
Anna Krylov is a Professor of Chemistry at the University of Southern California. She is a world-renowned theoretical chemist and is especially known for her advancement of CCSD, EOM-CCSD and spin flip methods.
Daniel Lambrecht is an Assistant Professor of Chemistry at the University of Pittsburgh, and specializes in computational studies of catalysis, spectroscopy and materials. He has made vital contributions to Q-Chem's MP2, molecular dynmamics and density embedding capabilities.
John Herbert is an Associate Professor of Chemistry at Ohio State University. He has led cutting-edge research on the development of new excited states density functionals, QM/MM methodologies, implicit solvation models, fragmentation methods, and other biochemical and photochemical simulation techniques, which has led to a wide range of improvements to the Q-Chem software.
Zhengting Gan is Q-Chem's Head of Software Development and Head of Customer Relations. Among his numerous contributions to Q-Chem, he has significantly advanced Q-Chem's parallel capabilities (especially for DFT calculations), and has also modernized Q-Chem's coding framework for faster DFT and TDDFT calculations.

Re: Q-Chem webinars 2012-2013
Yihan Shao #34049 06/13/14 01:02 PM
Joined: Jun 2009
Posts: 22
Y
Forum Member
OP Offline
Forum Member
Y
Joined: Jun 2009
Posts: 22
Dear Colleague,

Q-Chem would like to invite you to a user workshop in conjunction with the 248th American Chemical Society National Meeting to be held at Berkeley, California. The workshop will be held from 10:30 a.m. - 6:00 p.m. on Saturday, August 9, 2014.

Q-Chem is a comprehensive ab initio package and Q-Chem 4.2 release includes the latest theoretical/computational advances from Q-Chem's over 150 developers.

At the workshop, we will give an overview of the Q-Chem software package, especially those new features from the latest 4.2 release, and will provide hands-on tutorials of how to use the Q-Chem Program. We will highlight:

· density functional theory (DFT) and wave function theory (especially perturbation theory and coupled-cluster methods) for ground and excited-states;
· new tools for studying chemical reactions;
· application of quantum chemistry methods in energy and materials research;
· energy decomposition analysis;
· QM/MM calculations;

and the IQmol user graphic interface, which is fully integrated with Q-Chem.

The complete schedule is available at http://www.q-chem.com/wssf14_sched.html.

All workshop participants will receive a free four-month license for unlimited use of Q-Chem 4.2. Space is limited to 75 registrants, so please register as soon as possible at http://www.q-chem.com/wssf14_regist.html. Workshop participants can also sign up for one-to-one meetings with one of our speakers.

With the turbo-charged computational efficiency and the state-of-the-art theoretical methods developed by the most reputable research groups in the field, Q-Chem 4.2 is your ultimate tool to explore the frontiers of computational chemistry. This workshop provides an excellent opportunity for you to learn the basics, as well as to gain some additional expertise in effectively using Q-Chem for your research projects. We look forward to seeing you at Berkeley.

Happy Computing,

The Q-Chem Team

Re: Q-Chem webinars 2012-2013
Yihan Shao #35798 07/12/16 03:49 AM
Joined: Jun 2009
Posts: 22
Y
Forum Member
OP Offline
Forum Member
Y
Joined: Jun 2009
Posts: 22
Dear Colleagues,

Q-Chem would like to invite you to a user workshop in conjunction with the 252th American Chemical Society National Meeting (http://www.acs.org/content/acs/en/meetings/fall-2016.html) in Philadelphia, Pennsylvania.

Q-Chem is a comprehensive ab initio software package, and the Q-Chem 4.4 release includes the latest theoretical/computational advances from Q-Chem's over 150 developers.

At the workshop, we will give an overview of the Q-Chem software package, especially those new features from the new 4.4 (released May 2, 2016), and will use the IQmol graphical interface to provide hands-on tutorials of how to use the Q-Chem Program. We will highlight:
- Basic QM Calculations;
- Geometry Optimization and Chemical Reactions;
- Excited States;
- Lecture: Advanced Q-Chem Calculations.

All workshop participants will receive a free four-month license for unlimited use of Q-Chem 4.4. There is a nominal charge of $25 for this workshop since dinner will be served. Space is limited to 75 registrants, so please register at http://www.q-chem.com/wsPhil16_regist.html as soon as possible.

We look forward to seeing you in Philadelphia.

Happy computing,


The Q-Chem team

Page 2 of 2 1 2

Moderated by  lennart, rmv 

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.4
(Release build 20200307)
Responsive Width:

PHP: 7.3.31-1~deb10u1 Page Time: 0.008s Queries: 28 (0.005s) Memory: 0.7669 MB (Peak: 0.8373 MB) Data Comp: Off Server Time: 2021-12-01 00:37:29 UTC
Valid HTML 5 and Valid CSS