https://www.selleckchem.com/products/limertinib.html 9 mg/kg.The so-called protobranching phenomenon, that is the greater stability of branched alkanes with respect to their linear isomers, represents an interesting challenge for approaches based on density functional theory (DFT), since it requires a balanced description of several electronic effects, including (intramolecular) dispersion forces. Here, we investigate this problem using a protocol recently developed based on double-hybrid functionals and a small basis set, DH-SVPD, suited for noncovalent interactions. The energies of bond separation reactions (BSR), defined on the basis of an isodesmic principle, are taken as reference properties for the evaluation of 15 DFT approaches. The obtained results show that error lower than the so-called "chemical accuracy" ( less then 1.0 kcal/mol) can be obtained by the proposed protocol on both relative reaction energies and enthalpies. These results are then verified on the standard BSR36 data set and support the proposition of our computational protocol, named DHthermo, where any DH functional, such as PBE-QIDH or B2PLYP, provides accurate results when coupled to an empirical dispersion correction and the DH-SVPD basis set. This protocol not only gives subchemical accuracy on the thermochemistry of alkanes but it is extremely easy to use with common quantum-chemistry codes.Guided ion beam tandem mass spectrometry (GIBMS) is used to investigate the energy-dependent threshold collision-induced dissociation (TCID) of the two protonated isomers (protomers) of p-aminobenzoic acid (p-ABA). The O-protomer of p-ABA (protonated at the carbonyl oxygen) was generated via electrospray ionization (ESI) from a methanol/water solution, whereas the N-protomer (protonated at the amine) was produced via ESI from an acetonitrile/water solution. The two protomers are clearly distinguishable from differences in the onsets of the fragmentation channels and in the abundance and identity of