We present Far Ultraviolet Spectroscopic Explorer and Space Telescope Imaging Spectrograph observations of high-ionization interstellar absorption toward HD 14434 [ ( l , b ) = ( 135 . { } ^ { \circ } 1 , -3 . { } ^ { \circ } 8 ) ; d \sim 2.3 kpc ] , an O5.5 V star in the Perseus OB1 Association .
Intermediate-velocity interstellar Si iv and C iv absorption is present at V _ { LSR } 
= -67 km s ^ { -1 } , while low-ionization gas associated with the Perseus arm is detected at \sim -50 km s ^ { -1 } .
Neither N v nor O vi is detected at V _ { LSR } = -67 km s ^ { -1 } ; although Al iii and Fe iii , tracers of warm ionized gas , are seen .
The high-ion column densities in the -67 km s ^ { -1 } component are \log [ N ( C iv ) ] = 13.92 \pm 0.02 cm ^ { -2 } , \log [ N ( Si iv ) ] = 13.34 \pm 0.02 cm ^ { -2 } , \log [ N ( N v ) ] \leq 12.65 cm ^ { -2 } , and \log [ N ( O vi ) ] \leq 13.73 cm ^ { -2 } ( 3- \sigma limits ) .
The observed C iv/Si iv ratio of 3.8 \pm 0.3 in this intermediate-velocity cloud ( IVC ) is similar to the Galactic average ( 4.3 \pm 1.9 ) .
Our analysis of the Si iv and C iv line widths yields a temperature of T \sim 10,450 \pm 
3,400 K for this component .
At this low temperature , neither Si iv nor C iv can be produced via collisions .
We investigate several photoionization models to explain the intermediate-velocity Si iv and C iv absorption toward HD 14434 .
Photoionization models employing cooling of a hot ( T \sim 
10 ^ { 6 } K ) diffuse plasma as the source of ionizing radiation reproduces the observed properties of the IVC toward HD 14434 quite well .
The hot plasma responsible for the ionizing radiation in these models may be attributed to hot gas contained in a supershell in or near the Perseus Arm or from a more generally distributed hot ionized medium .