A vacuum ultra-violet photolysis of ethyl bromide was studied in the pressure range of 0.5 - 19.9 Torr and at 123.6 nm Krypton resonance line The pressure effect by adding an inert gas, i.e., He, was also observed. In the observation the monatomic gas is found to be no effect in the reaction. A scavenger effect of the reaction was performed by adding a radical scavenger No gas and was found to be quite efficient to scavenge a radical product $C_2H_6$.
The observation showed $C_2H_4$ as a major reaction product and which was interpreted in terms of a molecular elimination. Nontheless $Φ_{C_2}_{H_4}/Φ_{C_2}_{H_6}$ decreased with pressure increase. This observation may be attributed by the existance of two electronically excited states. One proceeds to the molecular elimination and other to carbon-bromine bond fission.
The excitation and the decomposition mechanisms between two excited states and the reaction products were interpreted in terms of the first excitation which proceeds the molecular elimination, and the second excitation which resulted from the first excitation state by collisional cross over decomposes by carbon-bromine bond fission.
123.6nm 의 광을 내는 크립톤 램프를 이용하여 에틸 브로마이드의 광분해 반응을 0.5 - 19.9Torr 의 시료 압력 범위에서 행하였다. 첨가물로서 헬륨을 넣고 실험했으나 단원자 기체의 압력효과는 나타나지 않았다. 라디칼 스케빈져로써 NO 를 첨가했을때는 라디칼 반응의 생성물인 에탄의 생성은 매우 효과적으로 억제되었다.
분자이탈반응의 생성물인 에틸렌이 주 생성물이었으나 분자이탈반응의 생성물과 라디칼 반응의 생성물의 비율은 압력의 증가에 따라 감소됐고 이러한 현상은 두가지 들뜬상태로서 설명돼었다. 첫번째 들뜬 상태에서는 HBr 분자 이탈반응을 일으키거나 충돌에 의하여 다른 들뜬상태로 전이한다. 충돌에 의하여 생긴 두번째의 들뜬상태에서는 탄소와 브롬 사이의 결합을 끊는 반응이 주로 일어난다.