I'm currently getting ready to apply to graduate programs in Chemistry, and am beginning to contact potential advisors. My problem is that until recently, I was planning to focus on field X, but have realized that I cannot see myself doing a PhD in this field.
After reading some papers in field Y, I am really excited about the possibility of doing research in this field, and have identified some potential advisors in field Y.
The problem is that all of my previous experience is in field X, and I don't really have any experience in field Y. Should I address my reasons for deciding not to pursue field X? And how do I demonstrate my sincere interest in field Y?