Molecular Orbitals (MOs) are linear combinations of Atomic Orbitals (AOs), which in turn are linear combinations of other functions called ‘basis functions’. A basis, or more accurately a basis set, is a collection of functions which obey a set of rules (such as being orthogonal to each other and possibly being normalized) with which all AOs are constructed, and although these are centered on each atomic nucleus, the canonical way in which they

Compound 2 represents the first structural example of a 12 e− auride complex, with a pseudohalide/hydride nature in bonding.

I have written about extracting information from excited state calculations but an important consideration when analyzing the results is the proper use of the keyword density . This keyword let’s Gaussian know which density is to be used in calculating some results. An important property to be calculated when dealing with excited states is the change in dipole moment between the ground state and any given state.

Prof. Mario Molina was awarded the Nobel Prize in Chemistry in 1995, the same year I started my chemistry education at the chemistry school from the National Autonomous University of Mexico, UNAM, the same school from where he got his undergraduate diploma. To be a chemistry student in the late nineties in Mexico had Prof.

This is a guest post by our very own Gustavo “ Gus ” Mondragón whose work centers around the study of excited states chemistry of photosynthetic pigments. When you’re calculating excited states (no matter the method you’re using, TD-DFT, CI-S(D), EOM-CCS(D)) the analysis of the orbital contributions to electronic transitions poses a challenge.

The Computational Chemistry Comparison and Benchmark DataBase (CCCBDB) from the National Institute of Standards and Technology (NIST) collects experimental and calculated thermochemistry—related values for 1968 common molecules, constituting a vast source of benchmarks for various kinds of calculations. In particular, scaling factors for vibrational frequencies are very useful when calculating vibrational spectra.

Having a paper rejected is one of the certainties of academic life. While there are some strategies to decrease the probability of facing a rejection, today I want to focus on my tips to deal with them—particularly for the benefit of younger scientists.

For the past few weeks, some chemists of the worldwide Latinx community have been cooking an online project devoted to showcase the important contributions to chemistry made by workers, students, and researchers from Latinamerican origin. The result is the #LatinXChem Twitter Poster Contest which will take place 7th September during a 24 hour span and the corresponding Twitter account @latinxchem (go follow it now!

The admission process for graduate studies at the National Autonomous University of Mexico (UNAM) is about to begin and I have wide open spaces in my lab for people interested in getting a PhD in the field of applied computational chemistry.

The canonical molecular orbital depiction of an electronic transition is often a messy business in terms of a ‘ chemical ‘ interpretation of ‘ which electrons ‘ go from ‘ which occupied orbitals ‘ to ‘ which virtual orbitals ‘. Natural Transition Orbitals provide a more intuitive picture of the orbitals, whether mixed or not, involved in any hole-particle excitation.

As a continuation of our previous work on estimating pKa values from DFT calculations for carboxylic acids, we now present the complementary pKb values for amino groups by the same method, and the coupling of both methodologies for predicting the isoelectric point -pI- values of amino acids as a proof of concept.