In an effort to slow emigration of whites with important jobs. Rhodesia's government is offering financial bonuses to civil servants and military personnel who agree to remain in the country after the introduction of black rule in Apil.

The constitution of Rhodesia-Zimbabwe, as the black-governed state is to be called, is designed to give whites far greater influence in the army, police, judiciary and civil service than their proportion of the population would warrant.

Nevertheless, the whites' confidence is being drained by the growing war and by lack of any indication from Western governments that they intend to provide diplomatic, financial or military aid once black majority rule in effect.

Last year, 18,000 whites left Rhodesia, the largest number since the former colony unilaterally declared independence from Britain in 1965.

Plans to offer financial inducements to those whites who remain were announced Aug. 29 by the biracial government's ruling Executive Council, made up of Prime Minister Ian Smith and three black leaders.

Details of the plans have been released only redently, however. Smith indicated late last year that priority would be given to members of the armed forces because maintenance of order was the government's first job.

In a meeting with army and intelligence officers Jan. 29, Rhodesia's army commander, Lt. Gen. John Hickman, reportedly said military personnel agreeing to renew contracts until April 30, 1980, could pick up an $862.50 bonus immediately.

After that, those deciding to leave Rhodesia could have pension payments substantially increased and in some cases doubled, deposited in a bank outside the country tax free, according to sources.

Hickman also hinted that even greater incentives would be offered later, one source said. Informed observers believe that the longer a Rhodesian remains after the advent of black rule, the bigger rewards he will get from the government.

"I want to buy at least a year, and after that, perhaps another one," Hickman reportedly said. His remark reflects what appears to be the prevalent attitude among white Rhodesians -- that the first year of the new state will be the crucial one, revealing whether international recognition will come and whether the war can be stopped.

The audience pressed "hard" questions on Hickman, but most welcomed the offer, a source said.

One of the questions frequently put by whites to their leaders these days is: "Are they prepared to organize a coup if the black leaders do not abide by thr constitution?"

Hickman reportedly gave what has been the standard noncommittal answer of most white officials: "He smiled and said 'Let me handle that,'" said one source. The army general, however, reportedly reminded the officers that under the new constitution, which whites approved in a referendum Jan. 30, white control over the army is virtually guaranteed for the first 10 years of black majority rule.

Although 80 percent of Rhodesia's security forces are black, most of the officers are white. Observers here believe that their continued participation is essential to maintain the army's current standoff with the antigovernment black nationalist guerrillas who are said to operate in 80 percent of the country.

Similar inducements are expected to be given to police, civil servants and the judiciary.

Most of the country's estimated 230,000 whites regard the retention of at least a nucleus of whites as necessary to keep the bureaucracy running efficiently.

Although Rhodesia has an estimated 10,000 black university graduates, one of the highest percentages in Africa, many are living outside the country. Others who are in Rhodesia have been kept out of resonsible positions in the civil service by recially discriminatory practices.

The financial guarantees being offered are similar to those former secretary of state Henry Kissinger proposed when he was trying to arrange a majority rule settlement between Rhodesians whites and black nationalist leaders in 1976.

Under the Kissinger plan, white farmers, who make up the backbone of Rhodesia's economy, would have been guaranteed a sum drawn from a fund created by the United States and its Western allies. The longer a farmer remained in the blackrun state, the more of his investment he would eventually have been able to receive outside the country. That plan was shelved when the Kissinger effort fell through.

The offer to give military personnel pensions outside the country raises the question of where Rhodesia will acquire the foreign currency to keep its promise if a large-scale exodus of whites occurs. The country has been strapped for foreign reserves as the result of 14 years of economic sanctions imposed when it rebelled against Britain.

The government is hoping either that it will never have to make good on its promise or that international recognition and lifting of sanctions will occur. There have been unconfirmed reports that the government has secretly been offered a large amount of money by a friendly country.