The best way to avoid appearing unprofessional in documentation is too keep things strictly to the facts and true information of the situation. Avoid editorial phrases such as "I think...", "I felt...", "In my opinion...", etc. Indirect editorials should be avoided too; these are phrases such as "The worst [incident] was ...", "Even better...", "Interestingly [enough],...". These phrases prioritize or compare other notes and do so without using evidence/facts. Editorializing can make you appear over emotional (something you will have to combat, sadly). A good method for your situation would be to state all the facts with minimal (i.e. none) editorials. At the end of the documentation of the incident(s) you can state the following which serves a summary and place to express your emotional perspective. This approach lends your emotional perspective to the situation without coloring the documentation.
"As I have stated [above], the noted incidents have left me feeling
[uncomfortable, uneasy, unsettled and concerned for my personal
safety.] I feel this behavior [is both unprofessional and borders upon
sexual harassment]. No employee should be treated like this nor feel
this way concerning their job, colleagues, manager, or company. I
would like [to be moved to another department or assigned another
Obviously the above is just a rough template and you should express yourself in your own professional sense, but do not go overboard (i.e. keep it to a paragraph and summation). This presents your side of the case in a professional manner while accomplishing 4 key principles:
- Provide the most accurate incident information possible
- Maintain a professional image at all times
- Express your concerns and self in a factual and business motivated sense
- Show an appropriate level of emotional involvement and effect
Remember, documenting a case (assuming the goal is to make a change of some sort) requires an extreme level of control and discipline. Knowing when to add emotionally charged responses and statements are critical to achieving this goal. On some level, you are manipulating your readers and any master manipulator will tell you, the cardinal rule is to keep your emotions in check so they can be properly utilized when needed. Depending on the level this gets too, the more factual you sound the better you look (both in person and on paper). Of course being robotic about a situation will be just as bad as being hysterical.
As Joe S. stated, if this has been a reoccurring issue and you plan on taking legal action then you should indeed consult a lawyer on the specifics. There is a specific way to present harassment cases in court and knowing the approach a legal professional will take is the best (if you plan on going that far).