I don't think so Vito. The entry of the USSR into the Pacific war merely confirmed the Emperor's decision to surrender. Keep in mind that the Soviets had been successfully battling the Japanese in China and Korea ever since Germany's surrender. So, the declaration of war was just a formality. For the first time during the war, Hirohito used his Godlike position to command the Japanese armed forces to lay down their arms. The surrender message itself by the Emperor was unheard of since the Emperor never spoke to his people. The Atomic bombs were what convinced him.

"Generosity. That was my first mistake."
"Experience must be our only guide; reason may mislead us."
"Instagram is Twitter for people who can't read."