Introduction to Quantum Theory

2021

CHEM 172.41 Physical Chemistry 2, Lecture 2nd sem, A.Y. 2020-2021, Ateneo de Manila University

Progress in Theoretical Chemistry and Physics, 2002

2012

Provided by the author(s) and University College Dublin Library in accordance with publisher policies. Please cite the published version when available. Downloaded 2016-05-08T19:11:08Z Some rights reserved. For more information, please see the item record link above.

Berichte der Bunsengesellschaft für physikalische Chemie, 1998

A collection of 22 introductory exercise problems for the course "Quantum Chemistry and Spectroscopy (QCS)", Dept. of Science, Roskilde University. (Error in Problem 8: J in line 6 should be squared)

Recent experiments have demonstrated that the electron transmission yield through chiral molecules depends on the electron spin orientation. This phenomenon has been termed the chiral-induced spin selectivity (CISS) effect, and it provides a challenge to theory and promise for organic moleculebased spintronic devices. This article reviews recent developments in our understanding of CISS. Different theoretical models have been used to describe the effect; however, they all presume an unusually large spin-orbit coupling in chiral molecules for the effect to display the magnitudes seen in experiments. A simplified model for an electron's transport through a chiral potential suggests that these large couplings can be manifested. Techniques for measuring spin-selective electron transport through molecules are overviewed, and some examples of recent experiments are described. Finally, we present results obtained by studying several systems, and we describe the possible application of the CISS effect for memory devices. 263 Annu. Rev. Phys. Chem. 2015.66:263-281. Downloaded from www.annualreviews.org Access provided by Weizmann Institute of Science on 05/18/15. For personal use only. Click here for quick links to Annual Reviews content online, including: • Other articles in this volume • Top cited articles • Top downloaded articles • Our comprehensive search Further ANNUAL REVIEWS 264 Naaman · Waldeck Annu. Rev. Phys. Chem. 2015.66:263-281. Downloaded from www.annualreviews.org Access provided by Weizmann Institute of Science on 05/18/15. For personal use only. www.annualreviews.org • Spintronics and Chirality 265 Annu. Rev. Phys. Chem. 2015.66:263-281. Downloaded from www.annualreviews.org Access provided by Weizmann Institute of Science on 05/18/15. For personal use only.

Molecular Physics, 2014

Advances in molecular quantum chemistry contained in the Q-Chem 4 program package Permalink https://escholarship.org/uc/item/9wn3w79b Journal Molecular Physics, 113 A summary of the technical advances that are incorporated in the fourth major release of the Q-CHEM quantum chemistry program is provided, covering approximately the last seven years. These include developments in density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster and perturbation theories, methods for electronically excited and open-shell species, tools for treating extended environments, algorithms for walking on potential surfaces, analysis tools, energy and electron transfer modelling, parallel computing capabilities, and graphical user interfaces. In addition, a selection of example case studies that illustrate these capabilities is given. These include extensive benchmarks of the comparative accuracy of modern density functionals for bonded and non-bonded interactions, tests of attenuated second order Møller-Plesset (MP2) methods for intermolecular interactions, a variety of parallel performance benchmarks, and tests of the accuracy of implicit solvation models. Some specific chemical examples include calculations on the strongly correlated Cr 2 dimer, exploring zeolite-catalysed ethane dehydrogenation, energy decomposition analysis of a charged ter-molecular complex arising from glycerol photoionisation, and natural transition orbitals for a Frenkel exciton state in a nine-unit model of a self-assembling nanotube.

2004

We examine a post-Born-Oppenheimer approach based on a generalized electronic diabatic (GED) ansatz for electronuclear dynamics in external electromagnetic fields. The model is a quantum n-electron system interacting with a set of m classical positive charges located at j ¼ ðj 1 ; …; j m Þ in laboratory space. The system's Coulomb Hamiltonian is H C ¼ H e ðq; jÞ þ KðjÞ; where H e ðq; jÞ is its electronic-only part and KðjÞ is the kinetic energy for the background charges. The GED basis set {f k ðqÞ} diagonalizes H e ðq; jÞ; and the diabatic potentials Uðj; f k Þ ¼ U k ðjÞ ¼ kf k ðqÞlH e ðq; jÞf k ðqÞl q define local effective Hamiltonians, kf k lH C f k l q ¼ KðjÞ þ U k ðjÞ; whose eigenfunctions {z kj ðjÞ} represent mass distributions for the positive charge backgrounds. The set {f k ðqÞz kj ðjÞ} diagonalizes the model Coulomb Hamiltonian, H C : The time evolution of a general quantum state is driven by the operator H 1 ðq; j; AÞ that couples the external transverse electromagnetic field A to the molecular system. The corresponding wave functions {F k ðq; j; AÞ} are represented in the basis {f k ðqÞz kj ðjÞ} using the superposition principle, and computed by diagonalizing H ¼ H C þ H 1 ðq; j; AÞ: A chemical reaction is signaled by changes in the amplitudes in the linear superposition. We discuss the implementation of the method for simulation purposes, and illustrate its application in the charge transfer process during H(1s) þ H þ collisions and a simplified three-state model of a chemical reaction. Contents 1. Introduction 276 2. GED ansatz 276 3. Post-BO scheme: process description 279 3.1. Charge transfer process in H(1s) þ H þ collisions 279 3.2. Simple chemical reactions: three-state model 283 3.3. Computer simulation schemes 286 4. Discussion 287 Acknowledgements 290 References 291

Hundred and forty-five novel molecules of Wittig-based Schiff-base (WSB), including copper(II) complex and precursors, were computationally screened for nonlinear optical (NLO) properties. WSB ligands were derived from various categories of amines and aldehydes. Wittig-based precursor aldehydes, (E)-2-hydroxy-5-(4-nitrostyryl)benzaldehyde (f) and 2-hydroxy-5-((1Z,3E)-4-phenylbuta-1,3dien-1-yl) benzaldehyde (g) were synthesised and spectroscopically confirmed. Schiff-base ligands and copper(II) complex were designed, optimised and their NLO property was studied using GAUS-SIAN09 computer program. For both optimisation and hyperpolarisability (finite-field approach) calculations, Density Functional Theory (DFT)-based B3LYP method was applied with LANL2DZ basis set for metal ion and 6-31G * basis set for C, H, N, O and Cl atoms. This is the first report to present the structure-activity relationship between hyperpolarisability (β) and WSB ligands containing mono imine group. The study reveals that Schiff-base ligands of the category N-2, which are the ones derived from the precursor aldehyde, 2-hydroxy-5-(4nitro-styryl)benzaldehyde and pre-polarised WSB coordinated with Cu(II), encoded as Complex-1 (β = 14.671 × 10 −30 e.s.u) showed higher β values over other categories, N-1 and N-3, i.e. WSB derived from precursor aldehydes, 2-hydroxy-5-styrylbenzaldehyde and 2-hydroxy-5-((1Z,3E)-4-phenylbuta-1,3-dien-1-yl)benzaldehyde, respectively. For the first time here we report the geometrical isomeric effect on β value.