G200 experienced decreasing airspeed at FL430 due to turbulence and increasing OAT. A descent initiated prior to receiving clearance results in a TCAS RA.

Narrative

I received a TCAS RA as a result of an emergency descent which I initiated. We were initially level at FL430 when we began to experience occasional moderate turbulence and increasing outside air temperature. This caused significant airspeed deviations and eventual loss of airspeed to nearly stall speed. We attempted contact with Air Traffic Control numerous times; but were unable to establish contact due to frequency congestion. When we eventually did contact ATC; we requested an immediate descent which I initiated simultaneously. At that time ATC directed an immediate right turn and declared an emergency. He also called out conflicting traffic which we were able to observe visually. We subsequently received a Resolution Advisory which I complied with by leveling the aircraft until clear of conflict. ATC then cleared us to FL400 and direct to our next flight planned fix. I contacted the ATC Controller via telephone after landing per his instructions. He indicated that he would submit a loss of separation report.