in the view of the traditional Chinese medicine liver "stores" feelings of anger and fear and other negative emotions. The free floating energy of life (called "Qi") and of the blood depends upon an normal liver function. Furthermore the movements of muscles and tendons depends upon an unimpaired "liver energy". The energy of the liver nourishes the eyes. In the chinese medicine, night blindness, waek eylight and chronic eye inflammations are manifestations of of an impaired liver function.
The most common dis-ease in the view of the chinese medicine is a stagnation of liver "Qi". The typical symptoms are feeling of being congested in the whole body, in particulatar in the muscles, irritability, inhibited emotionality, feelings of frustation and depression.
The underlying cause according to the chinese medicine are suppressed emotions like agression, anger, and rage.
Using some keywords mentioned above you should be able to find hits in google.
However, I would like to stress, that everything I cited above is true - at least for me.
I did 20 LFs so far. I ran through periods of great anger and rage, of depressions (every old emotion was freed up) while step by step I was approaching a state of enhanced mental clarity and awareness.
Apart from the beneficial physical aspects of Liver Flushing everybody should be aware that Liver Cleansing can bring about psychological insights and realizations in a "highspeed mode" that can be sometimes really frightening. One should have this in mind before starting the aventure of liver flusing. It helps to overcome these through periods with more calmness and confidence. And the end of tunnel will be a quasi newborn personality that is very much closer so the so called "real self" than the one before.
Coming back to your original question: Link between liver and emotions.
If you think in a very naive way it should be more than clear that a congested liver MUST affect emotional issues in any person. Because a congested liver is unable to detox ALL cells of the body the brain cells included the connection between mind and body (liver function) becomes obvious. Furthermore, a congested liver means that countless body functions are affected negatively and manifest as headache, fatigue, aches, sorenesses, intolerances, allergies etc. In other words these numerous nasty sensations/malfunctions will prevent you from fully enjoy your life and from being clear in mind. IMHO this is so easy to understand this even for a medical layperson.