# Density

Wednesday, October 1, 2008 - 11:15am - 12:05pm

Donald Truhlar (University of Minnesota, Twin Cities)

This lecture reports on work carried out in collaboration with

Yan Zhao.

We have developed a suite of density functionals. All four

functionals are accurate for noncovalent interactions and

medium-range correlation energy. The functional with broadest

capability, M06, is uniquely well suited for good performance

on both transition-metal and main group-chemistry; it also

gives good results for barrier heights. Another functional,

M06-L has no Hartree-Fock exchange, which allows for very fast

Yan Zhao.

We have developed a suite of density functionals. All four

functionals are accurate for noncovalent interactions and

medium-range correlation energy. The functional with broadest

capability, M06, is uniquely well suited for good performance

on both transition-metal and main group-chemistry; it also

gives good results for barrier heights. Another functional,

M06-L has no Hartree-Fock exchange, which allows for very fast

Tuesday, September 30, 2008 - 11:15am - 12:05pm

Gustavo Scuseria (Rice University)

This presentation will address our current efforts to develop

more accurate exchange-correlation forms

for density functional theory. There are two leading themes in

our current work: range separation and

local weights. On the first theme, I will present a three-range

hybrid functional and discuss the

rationale for the success of screened functionals like HSE and

LC-wPBE. On the second theme, the

emphasis will be on new metrics for local hybridization and

local range separation. Much of the focus

more accurate exchange-correlation forms

for density functional theory. There are two leading themes in

our current work: range separation and

local weights. On the first theme, I will present a three-range

hybrid functional and discuss the

rationale for the success of screened functionals like HSE and

LC-wPBE. On the second theme, the

emphasis will be on new metrics for local hybridization and

local range separation. Much of the focus

Tuesday, September 30, 2008 - 10:20am - 11:10am

Kieron Burke (University of California)

Recent work in my group has focussed on the semiclassical

origins of density functional theory, and how much of modern DFT

can be understood in these terms, including the limitations of present

approximations. I will discuss this in detail for model systems,

describing a method that avoids DFT altogether.

This leads to a grand algorithmic challenge, whose solution could

revolutionize electronic structure calculations, by allowing much

larger numbers of electrons to be tackled.

origins of density functional theory, and how much of modern DFT

can be understood in these terms, including the limitations of present

approximations. I will discuss this in detail for model systems,

describing a method that avoids DFT altogether.

This leads to a grand algorithmic challenge, whose solution could

revolutionize electronic structure calculations, by allowing much

larger numbers of electrons to be tackled.

Monday, September 29, 2014 - 3:15pm - 4:05pm

Frederick Manners (University of Oxford)

A simple argument of Erdos shows that every set of integers has a subset of relative density at least 1/3 that is sum-free, i.e. contains no solutions to x+y=z. He conjectured that the constant 1/3 is best possible.

This conjecture was recently proved by Sean Eberhard, Ben Green and the speaker. A key component of the proof is a structural result concerning sets of integers with doubling constant strictly less than 4.

We will attempt to outline the proof of the sum-free statement, with an emphasis on the role of this doubling 4 lemma.

This conjecture was recently proved by Sean Eberhard, Ben Green and the speaker. A key component of the proof is a structural result concerning sets of integers with doubling constant strictly less than 4.

We will attempt to outline the proof of the sum-free statement, with an emphasis on the role of this doubling 4 lemma.

Saturday, September 27, 2008 - 2:00pm - 3:00pm

John Perdew (Tulane University)