Cross sections for 3064 A band emission produced in collisions of 50--250 keV protons with water molecules in water vapor

Emission by excited products of collisions between 50--250 keV protons and H2O molecules in water vapor has been studied in the wavelength region 1050--3300 A. The relative single collision cross sections for emission of 3064 A (A 2Σ+--X 2Pi: O--O) band radiation by excited OH have been measured for proton kinetic energies of 50,150, and 250 keV. Measurements were also made of the relative cross section for emission of 3914 A (B 2Σ+/sub u/-X 2Σ+/sub g/:O--O) band radiation by excited N2+ produced in collisions of 50 keV protons with N2. Comparison of the relative OH emission cross sections with that obtained for N2+, and normalization of the 3914 A N2+ emission data to the absolute value for this cross section obtained by other investigators, yields values of the cross section for 3064 A band emission by OH in H++H2O collisions of (2.82 +- 1.42) x 10-18 cm2 at 50 keV, (1.79 +- 0.93) x 10-18 cm2 at 150 keV, and (1.69 +- 0.87) x 10-18 cm2 at 250 keV proton projectile energy