Hello,
I hope this message finds you well. I have just started to learn gaussian software. While running NLO calculations I used the keyword:
#p b3lyp/6-31g(d,p) geom=connectivity gfinput polar=(DCSHG, Cubic) CPHF=RdFreq
Later I came to know the common keyword used for NLO is:
# b3lyp 6-31G(d,p) Polar=(DCSHG,Cubic) CPHF=RdFreq.
Which is the most apt set of keyowrds. And what is the difference between # and #p.
The keyword "p" implies the print option, which give us machine-dependent information and converngence information in the output file.
Since Sunwoo Kang already explained the difference between # and #P, I'll remember that you can check the keywords and how they work using the documentation in gaussian's web page. https://gaussian.com/route/ for example.