Isoelectronic isogyric reactions

Field (CASSCF) Second-order Perturbation Theory (CAS-PT2) Configuration Interaction Core-Valence Correlation Effects Coupled-cluster Theory Experimental Data Evaluation and Quality Control G2 Theory Heats of Formation Isoelectronic Isogyric Reactions M0ller-Plesset Perturbation Theory Numerical Hartree-Fock Methods for Molecules r 12-Dependent Wavefunctions Relativistic Theory and Applications Spectroscopy Computational Methods Spin Contamination Transition Metals Applications,... 

Our objectives then are (1) to utilize unlabeled isogyric, valence isoelectronic isogyric, and isoelectronic isogyric reactions (see Reaction Class cation) to obtain accurate thermochemical data, (2) to identify the lowest calculational level that yields reliable results thereby minimizing the expense and CPU time required for the calculations, and (3) to predict enthalpies of formation (see Heats of Formation). 

Similarity is a relatively vague concept. Yet it is clear that GIF is somehow more similar to F2 than is HF or H2. We recognize CIF as valence isoelectronic to F2, i.e., it has the same number of heavy atoms and the same number and type of valence electrons. The use of valence isoelectronic isogyric reactions such as... 

Clearly there are several types of isoelectronic isogyric reactions for which the MPn/6-3IG(d,p) models do not have sufficient accuracy. In addition to the reactions containing the H, H2 pair, reactions containing species for which the extent of spin contamination is greatest (e.g., Ar2+, Table 2) tend to exhibit large variations in the MPn/6-31G(d,p) reaction enthalpies compared to the G2 reaction enthalpies. " However, there are many types of reactions in this category for which the errors cancel and the enthalpies calculated with these low level models are within 3 kcal mol" of those calculated with the G2 model. 

Each of the other theoretical models discussed in this work also has noticeably smaller average absolute differences between theory and experiment for isoelectronic isogyric reactions. For these models, however, valence isoelectronic isogyric and unlabeled isogyric reactions can also be employed to predict reaction enthalpies. Overall, the method of choice is the G2 method but its applicability will be limited by CPU time, memory, and disk space constraints. However, the G2(MP2) procedure is nearly as reliable and has the advantage of allowing larger systems to be studied. G2(MP2) calculations are preferred over MP4/6-31 lG(2df,2pd) calculations since the former reproduce both G2 and experimental results more accurately and require less memory, disk space, and CPU time. 

Carbocation Stabilities Comparison of Theory and Experiment Isoelectronic Isogyric Reactions. 

Joel F. Liebman University of Maryland Baltimore County, Baltimore, MD, USA Isoelectronic Isogyric Reactions 2 1439... 

---