Mrs/Miss el Aallaoui,

This chiefly depends on number of atoms per molecule and accuracy of theoretical method used to compute properties. Generally, G16 can be used to laptop.

The licence number should be printed on the disk(s) you receive when you purchase the Linux version of Gaussian 16.

As for the memory management, the use of memory in Gaussian depends on the type of calculation, the number of basis set (BS) functions N and the server architecture (32/64 bit). Nowadays, all PCs and workstations use 64 bit OSs.

First, be aware that Gaussian does not adopt SI units, so for Gaussian:

1MW = 1024 kW = 1024^2 W = 1048576 W = 8·1024^2 B = 8388608 B

There is a memory threshold M0, depending from the type of calculations and the highest angular momentum of the basis set. Since rarely BSs have momenta larger than f-functions, M0 can be safely taken as large as 4 MW (6 MW for MP2 freq calculations).

Under these conditions, the memory M for a 1-core calculation is:

M = M0 + 2N^2

For n cores M must be multiplied times n, while for 64 bit systems, it must be doubled. Therefore, for a n-core 64 bit workstation, the required memory M, in 8-byte W units, is:

M = 2n(M0+2N^2)

In order to know the actual total number of basis functions N, a test calculation can be run on the desired model compound (with the proper specification of BS), and in the output file the N value can be found after the basis set specification:

"N basis functions, ... primitive gaussians, N cartesian basis functions"

I hope this may help.

PS: for who may be interested, few years ago I prepared a small program (GaussMem, running under Linux, Win, macOS) to calculate M and convert in the most useful memory units. Contact me privately if interested.

Dear Muntadar Al-Yassiri,

just send me an email ([email protected]) and I shall be happy of sending you a copy of this small programme. Please specify the OS flavour you prefer!