Hi
There is OOTB functionality to send email to particular email address and you can feed these emails in Service desk using email eater.
Go to Management Module Editor->Elements->New Action->New SMTP Mail Action
Then add this action to the alert for which you want to send mail.
If you want to send more details about the alert you can use "Custom Email Formatter" field pack which you can find in community documents.
Please go through these threads it might help you:-
100919441
101612924
101352789
Thanks & Regards
Manirul