I generally (at least now) like the idea of merging quantum-machanics and quantum-chemistry into theoretical-chemistry.

However, the use of theoretical-chemistry is very vague and broad at the same time. It may deal with all sorts of different models and theories, at least judging from the scope of the questions, this is the use of this tag.

• orbitals: Bonding in diatomic C2, a carbon-carbon quadruple bond?
• solid state chemistry: Are chiral quasicrystals possible?
• kinetics: Definitions of autocatalysis
• nanotech: What does the charge distribution around a Stone-Wales defect look like?
• general terminology and their application: What does "reaction coordinate" mean? What does it mean when a reaction has TWO reaction coordinates?

Unfortunately the tag wiki is incomplete at best and the scope of these questions is just mentioned as:

For questions seeking generalised answers deduced from or composed of theories regarding the chemical reactions involved.

We also have a general without description and only 5 questions, while theo-chem has 55.

A lot of these questions also deal with models that would generally be considered quantum-chemistry or physical-chemistry. Appropriate retagging would be in order, as I think that theo-chem defines the scope of the questions best (in comparison within the range organic-chemistry, inorganic-chemistry, ...).

We might then want to go ahead and create a tag like the proposed general, but with a more meaningful name, like general-theories, chemical-models, ... (I cannot think of good ones right now). But yet again I am not sure if we actually need that.

If we clean up this tag, i.e. removing it from those questions that fit better in other categories, then I think merging would be very well applicable.

In general I think that conjunctional tagging is more appropriate in most cases:

• quantum-mechanics is in the scope of physical-chemistry and theoretical-chemistry
• quantum-chemistry is (almost always) in the scope of computational-chemistry and theoretical-chemistry and there are even more specific tags

I generally (at least now) like the idea of merging quantum-machanics and quantum-chemistry into theoretical-chemistry.

However, the use of theoretical-chemistry is very vague and broad at the same time. It may deal with all sorts of different models and theories, at least judging from the scope of the questions, this is the use of this tag.

• orbitals: Bonding in diatomic C2, a carbon-carbon quadruple bond?
• solid state chemistry: Are chiral quasicrystals possible?
• kinetics: Definitions of autocatalysis
• nanotech: What does the charge distribution around a Stone-Wales defect look like?
• general terminology and their application: What does "reaction coordinate" mean? What does it mean when a reaction has TWO reaction coordinates?

Unfortunately the tag wiki is incomplete at best and the scope of these questions is just mentioned as:

For questions seeking generalised answers deduced from or composed of theories regarding the chemical reactions involved.

We also have a general without description and only 5 questions, while theo-chem has 55.

A lot of these questions also deal with models that would generally be considered quantum-chemistry or physical-chemistry. Appropriate retagging would be in order, as I think that theo-chem defines the scope of the questions best (in comparison within the range organic-chemistry, inorganic-chemistry, ...).

We might then want to go ahead and create a tag like the proposed general, but with a more meaningful name, like general-theories, chemical-models, ... (I cannot think of good ones right now). But yet again I am not sure if we actually need that.

If we clean up this tag, i.e. removing it from those questions that fit better in other categories, then I think merging would be very well applicable.

In general I think that conjunctional tagging is more appropriate in most cases:

• quantum-mechanics is in the scope of physical-chemistry and theoretical-chemistry
• quantum-chemistry is (almost always) in the scope of computational-chemistry and theoretical-chemistry and there are even more specific tags