5.1 Make Multiwfn support more quantum chemistry programs

Although currently Multiwfn is able to directly accept Molden input file (.molden) as input file, only the file generated by a few programs is formally supported (see the related description in Section 2.5). If the Molden input file is generated by other programs then the analysis result may be incorrect. For these cases, you can use Molden2aim program written by Wenli Zou (https://github.com/zorkzou/Molden2AIM) to produce standardized Molden input file.

Using Molden2aim is easy. First move the Molden input file (e.g. ltwd.molden) into the directory where molden2aim.exe is placed, then properly modify its setting file m2a.ini, then boot up Molden2aim and follow its prompts to input commands, finally you will get ltwd_new.molden (standardized Molden input file) and may be other files (.wfn, .wfx, etc.).

In the .wfn file exported by Multiwfn and Molden2aim, orbital spin-types are explicitly written at the end of the wfn file via $MOSPIN field, this information is automatically loaded by Multiwfn.

Molden2aim can output GTFs with angular moment up to g. Although g GTFs is not originally defined in wfn format, these g GTFs can also be correctly identified and loaded into Multiwfn.

The "charge" field of the wfn file outputted by Molden2aim is the serial number of the element in periodic table rather than the effective nuclear charges, even if effective core potential (ECP) is used. This treatment is inconsistent with the wfn file outputted by Gaussian, in which "charge" is effective core charges when ECP is used (e.g. the "charge" of Au under Lanl2DZ is 19.0). So, if ECP is used and you want to calculate electrostatic potential, do not forget to modify "charge" field in the wfn file outputted by Molden2aim to effective nuclear charges.