An inversion-relaxation approach for sampling stationary points of spin model Hamiltonians.

نویسندگان

  • Ciaran Hughes
  • Dhagash Mehta
  • David J Wales
چکیده

Sampling the stationary points of a complicated potential energy landscape is a challenging problem. Here, we introduce a sampling method based on relaxation from stationary points of the highest index of the Hessian matrix. We illustrate how this approach can find all the stationary points for potentials or Hamiltonians bounded from above, which includes a large class of important spin models, and we show that it is far more efficient than previous methods. For potentials unbounded from above, the relaxation part of the method is still efficient in finding minima and transition states, which are usually the primary focus of attention for atomistic systems.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Rapid T1 Determination with Optimized Inversion Recovery Sequence

Introduction: There is continuing interest in rapid quantitative measurements of spin-lattice relaxation time (T1). Conventionally, an inversionrecovery (IR) sequence is used to determine T1, with logarithmic spacing of inversion recovery times (ti), a long pre-delays (td), and with data fitted to a single-exponential equation. Spin-echo (SE) or fast-spin-echo (FSE) techniques may be applied fo...

متن کامل

Optimizing sampling strategies for perfusion quantification using PASL

Arterial Spin Labeling (ASL) techniques potentially allow the absolute, non-invasive quantification of brain perfusion. This can be achieved either by fitting a kinetic model to the data acquired at a number of inversion times (TI) or by applying the model to a single TI assuming values for all other parameters. The accuracy of the model estimation strongly depends on the distribution of the TI...

متن کامل

A Fast Method for Obtaining a “Continuous” Sample of the Inversion-Recovery Curve Using Spatially Swept Adiabatic Inversion

The measure of the longitudinal, or T, , relaxation time in nuclear magnetic resonance experiments is a common diagnostic tool. There have been several methods proposed for measuring this parameter. Most of these methods measure the recovery of longitudinal magnetization after inversion or saturation. Conventional ( 180”-Ti90”) experiments measure the signal strength for a single temporal point...

متن کامل

Spin relaxation effects in photochemically induced dynamic nuclear polarization spectroscopy of nuclei with strongly anisotropic hyperfine couplings.

We describe experimental results and theoretical models for nuclear and electron spin relaxation processes occurring during the evolution of 19F-labeled geminate radical pairs on a nanosecond time scale. In magnetic fields of over 10 T, electron-nucleus dipolar cross-relaxation and longitudinal DeltaHFC-Deltag (hyperfine coupling anisotropy--g-tensor anisotropy) cross-correlation are shown to b...

متن کامل

Biologically aggressive regions within glioblastoma identified by spin-lock contrast T1 relaxation in the rotating frame (T1ρ) MRI

Spin-lattice relaxation in the rotating frame magnetic resonance imaging allows for the quantitative assessment of spin-lock contrast within tissues. We describe the utility of spin-lattice relaxation in the rotating frame metrics in characterizing glioblastoma biological heterogeneity. A 84-year-old man presented to our institution with a right frontal temporal mass. Prior tissue sampling from...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • The Journal of chemical physics

دوره 140 19  شماره 

صفحات  -

تاریخ انتشار 2014