Thermochemistry in Gaussian

Joseph W. Ochterski, Ph.D. April 19, 2000 The purpose of this paper is to explain how various thermochemical values are computed in Gaussian. The paper documents what equations are used to calculate the quantities, but doesn’t explain them in great detail, so a...

Vibrational Analysis in Gaussian

Joseph W. Ochterski, Ph.D. help@gaussian.com October 29, 1999 Minor updates: 17 June 2018, 20 August 2020 Get PDF file of this paper (you may need to Right-Click this link to download it). Abstract One of the most commonly asked questions about Gaussian is “What...

Comparing NMR Methods in ChemDraw and Gaussian

By James R. Cheeseman and Æleen Frisch Introduction NMR chemical shifts are an important tool in characterizing molecular systems and structures. Accordingly, predicting NMR spectra is an essential feature of computational chemistry software. In this article,...

Transition State Optimizations with Opt=QST2

Technical Note: The Synchronous Transit-Guided Quasi-Newton (STQN) Method, developed by H. B. Schlegel and coworkers [Peng93], uses a linear synchronous transit or quadratic synchronous transit approach to get closer to the quadratic region around the transition state...