In recent years

vacuum ultraviolet(VUV)optical properties have become of special importance for luminescent materials. The main interest has been in the development of new and efficient plasma phosphors to realize a gas discharge color picture display panel and mercury-free fluorescent lamps. Plasma phosphors are required to have high conversion efficiency under VUV excitation. Therefore

the strong absorption of phosphors in the VUV region is very important for the plasma phosphor. While compounds with aluminate groups have strong absorption in the VUV region. Thus VUV excitation spectra of BaMgAl

10

O

17

:

R

2+

(

R

=Eu

Mn)were investigated. The starting materials were Al

2

O

3

(4N)

MgO(A.R.)

BaCO

3

(4N)

En

2

O

3

(4N)and MnCO

3

(A.R.). They were thoroughly mixed in an agate mortar with a certain AlF

3

as flux. The mixtures were introduced in an alumina crucible and heated for 2 hours at 1 450℃ in the presence of carbon. The VUV excitation spectra of the visible luminescence of BaMgAl

10

O

17

:Eu

2+

is composed of two broad bands peaking at about 165 and 248nm. One band in the region from 200nm to 300nm is attributed to the absorption of the 4f

→

5d transition of Eu

2+

ions. The other band in the region from 120nm to 200nm is due to the host absorption. This result indicates that there is an energy transfer from host to Eu

2+

ions. Under 147nm excitation

the emission spectrum of Ba

0.9

Eu

0.1

MgAl

10

O

17

consists of a broad band at about 448nm

corresponding to the 4f

→

5d transition of Eu

2+

ions. The VUV excitation spectrum of BaMg

0.8

Mn

0.2

Al

10

O

17

consists of three broad bands in the range from 120nm to 240nm. The two bands located in the range from 120nm to 180nm are ascribed to the absorption of the host absorption. The band peaking at about 198nm is not attribute to the host absorption

it may be associated with the absorption of Mn

2+

. For a free ion of Mn

2+

the energy separation between

6

S(3d

5

)and

6

D(3d

4

4s)levels had known to be around 6.3×10

4

cm

-1

. Therefore

it may be assigned to one of these 3d

5→

3d

4

4s transitions. Under 147nm excitation

the emission spectrum is dominated by the green Mn

2+

-band at about 516nm. It is assigned to the transition from the lowest excited state to the ground state

i.e.

4

T1(

4

G)

→

6

A1(

6

S). The green emission of Mn

2+

indicates that Mn

2+

ions occupy the sites of Al

3+

which have tetrahedral coordination.