positive ionization mode vs negative ionization mode

[tobigithub]

Hi,
so I wonder how do we set positive ionization mode vs negative ionization mode in the qcxms.in for CID mode?

Is it automatically detected? Which would be nice, or do we set a specific keyword. The docs seem to only mention
positive ionization mode for CID (https://xtb-docs.readthedocs.io/en/latest/qcxms_doc/qcxms_ex.html?highlight=negative#dea-negative-ion-electron-ionization).

Tobias

[JayTheDog]

No, this is not yet implemented/fully tested. Settings have to be checked and the level of theory carefully considered. Might cost much more than pos. Ion mode because of larger basisfunctions that are needed to describe the negative charge accordingly.

[s645320041]

Hi,

I notice there is a 'ncid' in qcxms.in and wonder if it's a new function in QCxMS but just not mentioned in docs?
(https://xtb-docs.readthedocs.io/en/latest/qcxms_doc/qcxms_run.html)

[JayTheDog]

Hi,
this is a something that will be available in the next release. This runmode has accidentally slipped into the latest release, but was not yet finished nor tested at that time.

[JayTheDog]

The negative Ion mode in QCxMS is available since the update to Version 5.2.0.
Use that version with the keyword charge <integer> in the qcxms.in file to obtain negatively charged CID mass spectra.