The gas phase collisional disappearance of Mo(a 7 S 3 ,a 5 S 2 ,a 5 D J ) in the presence of N 2 , SO 2 , CO 2 , N 2 O, and NO over the temperature range 294-621 K and in the total pressure range 10-600 Torr is reported. Mo atoms were produced by the 248 nm photodissociation of Mo(CO) 6 and MoCl 4 and detected by laser-induced fluorescence. The room temperature depletion rate constant of Mo(a 5 S 2 ) + N 2 is (2.3 ( 0.7) × 10 -11 cm 3 s -1 ; the depletion rate constants of the a 5 D J are smaller and range from (16 ( 8) × 10 -12 for Mo(a 5 D 0 ) to (0.13 ( 0.04) × 10 -12 cm 3 s -1 for the other spin-orbit states. The depletion rate of all states of Mo by SO 2 are on the order of the collision rate. Mo(a 7 S 3 ) is found to be unreactive toward CO 2 , and the rate constant for the reaction of Mo(a 7 S 3 ) with N 2 O is expressed as k(T) ) (2.0 ( 0.5) × 10 -10 exp[-(9.8 ( 0.3) kcal mol -1 /RT] cm 3 s -1 . Termolecular kinetics are observed for Mo(a 7 S 3 ) + NO with k 0 ) (2.6 ( 0.3) × 10 -29 cm 6 s -1 , k ∞ ) (5.8 ( 0.5) × 10 -11 cm 3 s -1 , and F c ) 0.72 ( 0.07 at 296 K; the reaction rates for this reaction decrease with increasing temperature. Depletion rate constants of the reactions of the excited states of Mo with CO 2 , N 2 O, and NO are on the order of 10 -12 -10 -10 cm 3 s -1 ; the depletion kinetics are complex and involve significant energy transfers. Results indicate that the electron configuration of Mo plays a role in its depletion kinetics. In all cases, Mo(4d 5 5s 1 a 5 S 2 ) depletes faster than Mo(4d 4 5s 2 a 5 D J ). The inefficient reactions of Mo(a 7 S 3 ) with CO 2 and N 2 O are attributed to the production of spin-forbidden states.

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Case reportA 21 year old primipara was referred to our unit for advice regarding mode of delivery. The woman was 38 weeks pregnant and had an oblique lie. Her pregnancy had been uncomplicated. However, she had a large congenital haemangioma of the left buttock and thigh ( Fig. 1) extending to the lower leg and foot. There was a macular telangiectatic haemangioma that was associated with lateral venous varicosities that had developed over the past few years and had become worse in pregnancy. Both lower limbs were the same length, but the left leg showed hypertrophy of the soft tissues. The index, middle and little fingers of both her hands were unduly short. She had no significant past medical pregnancy.During her pregnancy, the woman developed varicose veins of the vulva, vagina and cervix. An ultrasound scan revealed distended lower uterine and cervical veins. The fetus was normally grown, the placenta was anterior and the liquor volume slightly reduced. We sought the opinion of a dermatologist, who diagnosed the Klippel-Trenaunay syndrome.The woman remained on the antenatal ward until 39 weeks of gestation. In view of the vulval, vaginal and cervical varicosities and a persisting oblique lie, we decided to deliver her by caesarean section. A midline vertical incision in the skin was performed and a classical caesarean section was carried out. A massive plexus of varicosities filled the uterovesical fold, extending over the lower uterine segment. The lower pelvic peritoneum was also involved. A baby girl was born who cried at birth. Her weight was 3.3 kg. Following delivery, an infusion of oxytocin was administered, which caused the uterus to contract well. The varicosities that had been so prominent before delivery shrunk down considerably. The estimated blood loss was 1500 mL and the woman received a transfusion of two units of blood. She made a good postoperative recovery. In view of the increased risk of thromboembolic disease, she was treated with enoxaparin 40 mg daily and elastic stockings for seven days. DiscussionThe Klippel -Trenaunay syndrome is a rare congenital disorder first described in 1900 1 . It consists of a triad of cutaneous port-wine capillary malformations, varicose veins and hemihypertrophy of soft tissues and bone. Fig. 1. Patient's left buttock and thigh showing haemangioma and associated varicosities.

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