Quantum free-energy calculations: A three-dimensional test case
نویسندگان
چکیده
An optimized integration scheme for calculating vibrational-rotational partition functions by the Fourier path-integral method, as presented in the previous paper [R. Q. Topper and D. G. Truhlar, J. Chem. Phys. 97, 3647 (1992)] is applied to a three-dimensional test case involving the coupled vibrational and rotational motions of a diatomic HCI molecule in Cartesian coordinates. Converged partition functions are calculated by the new Fourier pathintegral Monte Carlo scheme and by standard variational methods, and the two sets of results are compared. We obtain good agreement (2 %) between the two methods over a range of a factor of 20 in temperature.
منابع مشابه
pKa predictions of some aniline derivatives by ab initio calculations
: In this work, different levels of theory containing HF, B3LYP, and MP2 with different basis sets such as 6-31G, 6-31G*, 6-311G, 6-311+G, 6-31+G*, 6-31+G are used to predict relative acidity constants of some aniline derivatives. Three different kinds of radii containing UAHF, Bondi, and Pauling are used to study how cavity forms change acidity constants. In all cases, DPCM model is used to si...
متن کاملConjugate-gradient optimization method for orbital-free density functional calculations.
Orbital-free density functional theory as an extension of traditional Thomas-Fermi theory has attracted a lot of interest in the past decade because of developments in both more accurate kinetic energy functionals and highly efficient numerical methodology. In this paper, we developed a conjugate-gradient method for the numerical solution of spin-dependent extended Thomas-Fermi equation by inco...
متن کاملNon-perturbative phenomena in the three-dimensional random field Ising model
The systematic approach for the calculations of the non-perturbative contributions to the free energy in the ferromagnetic phase of the random field Ising model is developed. It is demonstrated that such contributions appear due to localized in space instanton-like excitations which exist only in dimensions D ≤ 3. It is shown that away from the critical region such instanton solutions are descr...
متن کاملشبیه سازی اثر بی نظمی و میدان مغناطیسی بر ترابرد کوانتومی نانوساختارهای دو بعدی مدل شده با تقریب تنگابست
In recent years, semiconductor nanostructures have become the model systems of choice for investigation of electrical conduction on short length scales. Quantum transport is studied in a two dimensional electron gas because of the combination of a large Fermi wavelength and large mean free path. In the present work, a numerical method is implemented in order to contribute to the understanding ...
متن کاملMolecular Dynamics and Docking Investigations of Several Zoanthamine-Type Marine Alkaloids as Matrix Metaloproteinase-1 Inhibitors
Zoanthamine-type alkaloids display a wide spectrum of biological effects. This study aimed to examine the inhibitory effects of norzoanthamine and its ten homologues of zoanthamine class on human fibroblast collagenase by modeling a three-dimensional structure of the ligands at collagenase using energy minimization, docking, molecular dynamics simulation and MM-PB/GBSA binding free energy calcu...
متن کامل