2023年1月31日 · If you have integrated that peak, you'd see the integration value is more than 3-protons of the real compound. That means your compound is really wet when you take the NMR. The following diagram shows ratios of water peak to TMS and residual $\ce{CHCl3}$ peaks in a typical $\ce{CDCl3}$ (with 99.8% $\ce{D}$ and 0.05% TMS) solvent bottle (Ref.1):

2017年6月22日 · First let's run an ordinary, restricted calculation. If you are not using the SCF(xqc) keyword, you should immediately notice, that something is wrong. %chk=bp86svp.rhf.sing.chk #p RBP86/Def2SVP/W06 DenFit ! Use density fitting to spead up calculation gfinput !

2023年2月27日 · Interesting because I had a similar issue trying to run a Coleman catalytic heater with kerosene. This lead to some checking of flash points and petroleum distillate definitions. The distillate "cuts" run from gasoline (flash point -23 C) to Coleman fuel, "white gas", or light naphtha (flash point - 4C) to kerosene (flash point + 38C).

2019年4月24日 · I'm trying to run DFT or other 1st principle simulation of Pyrope ($\ce{Mg3Al2Si3O12)}$ and Grossular $\ce{(Ca3Al2[SiO4]3)}$ unit cell structure. So, I'm looking for unit cell xyz periodic box structure of Pyrope and Grossular. I found some data from several places (here, here and here)

2023年4月28日 · I have been thinking of some ways: (1) find some possible conversions of my compounds to nominal identifiers (e.g. DrugBank ID) and extract 3D structures from those databases; (2) just run pyscf; (3) find some papers that predicts 3D structure from SMILES (does this kind of papers even exist?)

2015年10月12日 · $\begingroup$ Anyone involved in serious organic synthesis intuitively runs some form of gradient column if they're doing anything more complicated than a simple reduction or protecting group manipulation.

2017年6月8日 · 3. Solvent system. Although you say that "this solvent system has been used to run similar wax extracts", its always worth trying different eluents with your chromatography, unless your sample is identical to the prep you're following. A different modifier (formic acid or trifluoroacetic acid often work well), or different solvent mixtures ...

2016年4月14日 · 3 $\begingroup$ @Martin-マーチン I do not agree with you: this problem is very specific for a QChem program, so it is very unlikely that Computational Science people can say much about it, while many Chemist have experience with the given software.

2023年2月25日 · $\begingroup$ Based on both answers, when the run is finished it may be best to run a gradual gradient back to non-polar solvent (hexane) as well. $\endgroup$ – Robert DiGiovanni Commented Feb 25, 2023 at 12:31

Even if you consider a batch-wise process of generating ammonia (which, as orthocresol points out, isn’t the case), it is more efficient to run two batches in half the time for two sets of $15~\%$ than to run a single batch for twice the time to get an overall yield of maybe (note: This yield is a ballpark estimate) $25~\%$ — with a batch ...